I believe there is a captcha check during log-in, yes. But probably anyone with some tech knowledge would now give you the answer that this does not stop bots completely, otherwise there would not be issues with bots as a conclusion.
I have not yet clicked on the report button (and do not feel like testing it out by clicking on it under random posts), but I assumed it would notify the staff to check the corresponding comment/user. Maybe the system also tracks reports and acts accordingly if too many accumulate, but that could also easily be abused, so maybe a notification is all there is - simply because while we are managing our own pages, there is a 'parent' above us we (and especially 'normal' users) can ask for help.
So the basic answer to your question is: It does not... really change a thing. The person could still be the same amount of bot as they could not. Which of course brings us back to all the analyz-y stuff about overdoing and how to handle it by your own measurements.
I know what you mean with basically saying: No matter which route you take on this, you feel like you are overthinking anyways. Doing it on your own (specifically planning on how to do it) - overthinking. Asking others about the issue (Making it bigger than it is) - overthinking. Again, one part here is to read the room. Is it overthinking or just making sense to open another topic on this, for example. The other part is the solution I came up with (or actually still try to integrate more and more in my behaviour) - listening to my feeling. Because as you mention yourself, there always seems to be so much variety in how things could go and actually be, that with thinking alone you never can get to a satisfying conclusion. Came up with something yourself? Maybe you still forgot something or learn to do better next time. Asked someone? Maybe they only gave you their point of view? It can never be 'perfect' in that regard.
If you try listen to your feeling however, it usually turns out... as intended. That is at least my experience (and can sound not that convincing, I am aware). Sometimes it turns out right, because you did the most fitting action in your circumstance, sometimes it does turn out so-so, but usually because you were supposed to learn something from it. That is at least how I noticed a lot of times since I tried that approach. And even if it would be complete nonsense, you actively achieved the following: Not thinking too much about something were it is not required, and just do as you feel is right. And that is usually always beneficial. Because even if you have to think about a topic more, your feeling will tell you that as well, or you can learn something from doing what you felt was right to broaden your horizon.
In regards to some of your points:
Checking if a spammer or not for peace of mind: While I know that nagging feeling, I can assure just letting it rest at some point (especially if there is nothing to be gained) is the wiser choice. And it makes you think less, which is a win in that regard.
Discord Situation: This is actually something I think about from time to time, as well. You do not want to be unsympathetic to a person who just are how they are. Seems correct. But it is not as black and white there, either. Sometimes people have to learn and adjust their behaviour, at least as much as they are able to. And it is sadly a truth that we all only have so much attention and endurance to handle all kind of people and situations. You can only try to do your best, which again, for me means to listen to my feeling. That could mean waiting until a person leaves on their own eventually, getting into a situation where you can remove them, keeping them because it is fine, or even liking to have them around. It can still be a very diverse outcome, but without overthinking and doubting oneself.
And if your feeling tells you that it is a bot... at some point you have to make the decision if you want to kick them based on that - or not. Maybe you learn something from it, maybe it was the right decision to do because you needed to handle it that way to 'make it work' for you. And maybe they simply were a bot. Just as sometimes you just know some people are not that great and no matter how much you doubt yourself it turns out that you were right at the end. Again, quite wild amount of outcomes. You can only listen to yourself of what would be the best approach at that point in time.
Writing a second reminder: That is actually a really good solution. And if your only doubt is that it could come across awkward: Forget about that. Honestly, if you think it would make sense to approach the situation like that, just do it upfront: Tell them why you are asking again, what was missing from their last reply, give them some points they could answer on, and just be clear about it. What is the worst that could happen? That they did not like your polite honesty for not seeing why you did it? It may sound harsh from my side, but unless I have a good reason to believe they can nothing for it, it sounds like a problem on their side, not mine. So I can be upfront. I do not have to be afraid of making it awkward. We already are in that situation to begin with and it was not me starting to get us into that. And after being upfront and tackling all points, it may even give you a better view depending on how the person answers you once more.
Putting into spotlight: Yes, I meant the particular user. And yes, purely realistically speaking, you do have a point about how the discussion board is visited and by whom. I am just more of a person of 'the end does not justify the means'. It still seems not polite (or right) to me to put them into a spotlight. And at the end of the day, they could be a normal user liking your work - and they could potentially visit this discussion board. Feels kind of... not cool to me. But as said in my previous post, I can see why you did it. It made sense (at least to you). If not trying to be black and white, the world did not collapse on it. And yes, sometimes it is once again about reading the room: Would it work out this time? How would the other person react? Does it make sense in this situation? For example, your asking yourself what else of an option would there have been? In regards to the user here, as some have pointed out, either letting it be or try to solve it by yourself. For the teammate you had, maybe writing to them directly, instead of seeking an indirect solution where they may see you talked about them. Most of the time, people do not like that too much. But this can (and should) rely on how you read the room. Maybe it did make total sense there to do it like that. Who am I to put your situation into a box and say 'No'.
About ratings: I mean, what could you really do if a platform would be (potentially, not saying it is) infested with bots spamming positive or negative ratings? Hoping that it gets solved eventually, I assume. In that regard, I guess I would not mind either. I would not like fake ratings per se, I would love to get ratings that are truthful, but I cannot do anything against 'good' or 'bad' spam. If you are doing your work commercially, you would of course be driven to like one side more and still care about the other for obvious reasons. If you are doing it as a hobby, you could still care about the latter, but... it is really not worth it. I certainly would not.
About reviews/comments: Again, if you are going commercial, or just want your work to be recognized, than yes. Hoping for users to actually use the systems that matter would be great. Adding a detailed text in some form would be a bonus. From my point of view though: Ratings would be cool, yeah. But I would love for people to engage in the comments about it, no matter if just a short 'Really cool' or a 3 page essay about the principals of game design. Of course, especially if it comes down to 'really bad', you would hope for a more detailed feedback instead of leaving a negative 'impact' on your work. But that is also just how it is. Some people give their expression (sometimes justified, sometimes debatably not), and all you can do is accept and/or ask them for a more detailed answer.
Pinned topics: At the end of the day, it is always up to the mindset of the staff/moderator on how they see their surroundings they are working in. They could have felt like such a topic would make sense to pin as it is not clearly explained in the guidelines - which I agree with. And with some topics they may think it is doable in other ways. Which... is debatable. I often agree on it. Sometimes I feel like the guidelines have more topics which could be expanded upon, as well as some issues handled better on the site/board (Like the reminder of not asking about indexing within a spoiler tag at the top which feels like only 2% of visitors are actually reading). That being said: I am using this site for almost three years now, and while I can see need of improvement at some parts (for example the speed of updates and especially support handling requests/issues), one can see that they do care to do their job right - and they also do listen to their users. Which I do not take for granted nowadays.
... That last part got a bit sidetracked. What I wanted to write here is: It could be a viable suggestion to the team to maybe pin topics more often or think about how to improve the faq and guides on the discussion board. However, as mentioned last post, they probably have other matters to attend to - and as we all know, the usage of the discussion board is quite limited, so once again: I would not think too much about topics getting pinned or not, to be honest.