I've got Sims4 from fitgirl and anadius up and running for a friend. I can't speak for other titles, but for this is was as simple as starting it with lutris. Modding was a bit harder, but only because the prefix was more difficult to locate, once everything was in the right place it worked no issue.
Edit: i would also recommend to install asdf and with that then protonge.
You are right. I assumed they wouldn't test a new DE in an LTS version, but they, in fact, do that.