I was able to get a consistent 70+ fps with most things set to medium, 1440p with a 3900x and a rtx 2080 with dlss2 and a mod that helps performance without any noticable dregredarion I can tell.
Just from a a couple of nights playing Starfield. The combat ai does seem more interesting then with enemies jumping off ledges to get to you etc but not but a whole heck of a lot. L