Pairing an 5800x3D with a 5080

Yes, I know obviously an 9800x3D is better, but is it new system better to play exclusively at 4k? Is it that insane to stay on AM4?

Considering the 5080 is less traditionally strong in raster for an upgrade (but still a 70% boost coming from my 3080 10GB), it seems likely AI features are a must. So in reality this question is more play exclusively at 4k with DLSS on Quality.

So for a usage scenario of being limited to 120 FPS at 4k and using DLSS, is it really mandatory to do a full system refresh so I can hover around 120 FPS to make use of my TV's potential?

I'm not very inclined to spend the +- 1000-1200$ to do a full upgrade. All in all, if I sell my system as it is, with a new 5080 in the mix, I'm probably looking at $1500-600 to upgrade and refresh to AM5 with a new build. Am I right in thinking this isn't reasonable, or am I missing something?