Fixed. First, I got the GoG edition, then installed GoTR on that. Didn't work, although I was using the Heroic launcher, so that may have been related.
Then, I went back to the steam edition, uninstalled it. I happened to have the file location opened and I noticed there were still some files there. Then I reinstalled, deleted them, and reinstalled again, along with GoTR.
And the crashing stopped.
I have no idea why that fixed it. So, if any else is having this kind of problem, try deleting all the files manually, then reinstalling.
It may work, or not. I take no responsibility.