That warning shouldn't be a problem. Try without dynamic meshes, though that's mostly just affecting the areas within view of your land claim(s). I wouldn't bother reinstalling the game anymore. That's not going to do anything at this point. But try without mods just in case.
Since you built it, there wouldn't be any bloatware installed unless you installed it yourself. But if you did install any apps to improve performance in games, that could be the problem. The post I linked above also suggests that maybe the GPU is loose, which could be possible when building it yourself, or that the GPU might be failing. Unfortunately, unless you have a different GPU, you can't easily test that without buying a new GPU. Though you could run something like 3DMark to test your computer/GPU and see if you have any issues.
The person with the problem in that thread never responded to say if they solved the problem, so we don't know how they solved it (if they did).