So for reference, I game at 1440p 144 hz. I have an 11700k and a 3080ti. And it works well. You have to understand (especially if this is your first build) that not every engine is created equal. Unless you're playing older games or stuff like league of legends/Fortnite/rocket league you won't hit that fps cap. But with your rig you should be able to run most games on high/ultra settings around 80-110 frames given how demanding the title is. To future proof as you've said you want to get some life out of the system. I would suggest spending a little extra cash on a 7900xt. I saw some listed at microcenter.com for like $800. If that prices you out of building, then I would look at dropping your cpu, and moving to ddr4. But in total my suggestion would only be $350 more and the performance gain should be noticeable for a few years and it will pair better with your cpu.