If I wait for a good sale what nvidia GPU should I upgrade to if I only want to spend like 750 bucks max

This is my current setup. Yes it was an NZXT custom pre-built.

Ignoring potentially upgrading any other components, is there any worthwhile GPU I should consider upgrading to, assuming I only want to spend ~800 bucks at most (and then plan on selling my current GPU to make back some money for a net loss of like 400)

I currently just use a 4k OLED TV that's only 60hz so high FPS isn't a target but high resolution is