There is way for performance improvements ans DLSS type technologies to both exist. We are not at the pinnacle of graphical quality. Studios will not suddenly stop putting better graphics in games with the higher performance they get out of new cards, and allot that capability for more frames.
Even if you have better - newer GPUs, DLSS-type stuff will always allow you to get more performance out of your rig. I am not even talking about frame-grn since I have not tested that yet. Just the upscaling.
Same, I can recommend vesktop to at least have a dedicated window for it, + some customization. I used discord-sandboxed before, but that stopped working.