You will find 25-30 fps to be real important if you're only getting 20 fps. I was on a GTX 1080 when I moved to a 4k display. I quickly found the 1080 to be lacking in 4k capabilities. I then upgraded to a 2080 super. And while it performed MUCH better than the 1080 at 4k, it still didn't perform quite as well as I wanted it to, especially on visually demanding games like Witcher 3. I recently traded my 2080 Super for a 3080, and I'm finally in a 'happy place', performance wise. So if you can envision yourself moving to 4k anytime soon, go with the 3080, hands down. At the lower resolution you stated, honestly any of them will be quite playable at decent detail levels.