So... it's fixed?
I don't really know how, but I think it's working. Here's what I did.
I began to think "Well, it's the screen, maybe it's a graphics thing?" So I went to https://www.nvidia.com/download/index.aspx to redownload my graphics drivers from the source rather than through their GeForce Experience app.
Downloaded, installed, but I was knacked so I went to bed. Then today, I thought I'd try another game on the Godot Engine which was having the same issues. Low and behold, it was working. So I then tried Strive for Power, then Conquest. The issue is gone. I'm trying Conquest right now, and it's still going well.
I did have one crash, but that was when I went from the Mansion to Aliron. Game just froze. But compared to before, I've been playing for over 20 minutes and that was the only crash. So it's looking up for now.