Most games are graphics limited,and you have destroyed that limitation with a 3080ti.
9700K may have only 8 threads, but most games can not make effective use of more than 4-6 threads.
Multiplayer with many participants would be an exception.
See how you do with YOUR games before deciding.
Try this test:
In windows power options, limit your cpu max performance from 100% to 90% to simulate what a lack of cpu resource does to your games.
Certainly if i9-11900K is within your budget, that is going to be as good as it gets today.
But, in a year or so, intel and amd will have newer, stronger processors that need new motherboards and perhaps ddr5.
I might wait.