I had a 2080ti and 5900x and was constantly CPU limited, no matter what I did. I then changed the CPU for the 5800x3D and just like that was relentlessly GPU limited. Then I got a 3090 (not TI) and it’s now a mixture of both, with everything turned up to 11 and LODs at 200.
I also play an older Train Sim game which runs on DX9 and is notorious for being very heavy on CPU’s. Literally in the blink of an eye that game is now heavily weighted towards the GPU, and often has this 3090 completely maxed out.
Given it’s a simple swap, you’ll recoup some of the cost back by selling the 5800x and you don’t have to upgrade your motherboard and RAM etc it’s a no brainer. I was very sceptical to start with but have no regrets about making the change.
The only caveat to this though is that if you use your PC for things other than gaming, particularly processor intensive tasks, that has to have some bearing on your decision. Obviously it’ll be no different to the 5800x but I’d say it’s a smidge slower than the 5900x for this sort of thing. Gaming though, hands down winner.