NOTE: If you want to skip over my lengthy ramble and get right to the point, scroll to the bottom until you see the next bolded text!
This is a decent enough request, though I doubt it'll be integrated. I'm not terribly familiar with this game's development history, nor whether or not it's still in active development or not. In any case, players of games really need to understand just how much added work it is for a developer—especially an indie dev, who likely has a team of maybe one to five people working on their game, and typically each individual has a very specific portion of the game that they're in charge of, eg. art, music, design, code, etc.—to even add mod support to their game, let alone create and supply the players with the necessary tools to make and distribute those mods.
That said, there's are tools that can make the job simpler, and when a game is designed from the very beginning to support modding, the amount of added work is relatively small. The main hurdle is that the tools which devs use to design their games are usually either a) licensed (meaning, the dev paid for the right to use it) third-party (meaning, created by another company) tools which can't be legally redistributed to the players, as they're only licensed for the development team themselves, b) developed in-house (meaning, the devs of the game created the tools themselves), which are typically finicky, buggy, ugly, hacked-together tools that require a high degree of technical knowledge to use and are designed with very specific purposes in mind (meaning, they're difficult to use, usually have practically no documentation, and are made with the sole intention of them being utilized by the team for specific aspects of the game design). Sometimes, this isn't the case, and the tools used are free and open-source, in which case they are usually much more player-friendly.
Of course, all of that assumes that we're talking about modding more complex than a simple texture replacement. A lot of indie devs will get around this problem by making use of scripting engines for their game code—though, that's not the only reason they do this, and I'd even argue that the choice to use scripting languages for games is often not based on the fact that it makes modding easier, but rather that it makes development easier. Popularly, Lua is frequently utilized for this purpose, but many games will also use JIT C# scripts, or any number of other scripting language. Unity games are more likely to go the C# route or the Lua route, though.
In any case, back to the topic at hand: distribution of mods. This gets really tricky, because you're talking about the developer of a game that very likely is a passion project with negative profit margins; which is to say, if we compared the cost (in development time, eg man-hours, and money, eg spent on tools, assets, advertising, ) to the amount of inward cash flow the product generates, many indie games won't even manage to break even, instead starting technically in the red for their entire lifespans. Game development is not easy, it's incredibly time consuming, it's logistically difficult, and the competition is so fierce that most indie games are lucky to see even a small amount of sales, and those sales rarely manage to offset the project's costs. For all of these reasons, when you ask for the developer of such a game to not only build and provide the game itself, but also develop, manage, and host (and pay for that hosting) a website or webservice which allows the distribution of mods... yeah, that's asking for too much.
NOTE: Rambling over, the rest of this post discusses solutions.
With all of that said, I've seen some very clever solutions to this. The most obvious solution is to make use of a third-party service, such as mod.io or Nexus Mods, but these sorts of services often have strict rules about content, which can be a problem for adult oriented games, like the one we're discussing. The most clever solution I've seen to this problem is to make use of GitHub repositories for the hosting and distribution of mods. While GitHub does have content restrictions, they're often much more lenient and less restrictive. Even better, if you adjust this concept of "any git repository hosted on GitHub" to be "any git repository," you can now include even self-hosted Git repos (such as Gitea, Gogs, Bitbucket, etc.).
The way such a system works is absurdly simple, at least from a developer's perspective; it's also incredibly straightforward to make use of from a player's perspective, too. You simply include a git library with your game. Mod installation is done via the user providing the URL for a git repository. The game then downloads the repository and updates are done by simply synchronizing the repository. All your game needs now is a basic UI and a manager to handle this process and you've solved the problem of mod hosting.
The only instances where this might not work is with games that rely on mods including copyrighted content, such as rhythm games. For example, this wouldn't cut it for a game like Rhythm Doctor, because hosting copyrighted music is a dangerous game that sites like GitHub have zero interest in engaging in. For games like that, no pre-existing service is going to be open to hosting that sort of content.
In any case, to summarize, there's a very good set of reasons why you see indie devs relying on Discord for their modding community. It is, admittedly, extremely annoying and provides a less-than-stellar user experience. It requires users to join their Discord community, which may prohibit some players from engaging with mods at all. It's a shame, because using Discord for mods inevitably increases the friction for players and makes players less likely to bother with a feature that likely required significant effort to develop.
It'd be nice if more devs would try out imaginative solutions to the problem, though, rather than just throwing their hands up in the air and saying, "Well, what can ya do? Discord it is." Modding is, after all, once of the best ways to guarantee the longevity of your game, as it instills a sense of ownership within your community and gives the game a much longer shelf-life. Just look at Skyrim (horrible game IMHO, but to each their own) or any other game on that engine: people STILL play those games to this very day. Why? Because of the mods!