As mentioned, the guy states he plays competitive games, with no RT, at 1440p.... For his use case 6900XT is better in every way that matters... Slightly higher raster perf is worth everything.
As for DLSS being a selling point for a £1500 (lols) top of the range graphics card.... Well... <sigh>
Competitive games, even easier decision.
NVidia for reflex/ gsync. Freesync is a joke and freesync monitors in general have tons of issues.
Plus, drivers.
And once again, the complications of going from a 3080 to a 6900xt just for a few more frames in certain situations but overall having a crappier experience, nevermind issues with warranty and who knows what else? Not like the 6900xt is store bought. Its from a guy who wants the 3080 to mine so prolly mined that 6900xt too in who knows what conditions?
Hard pass.