Everything about latency. This section is mainly user/consumer discussion. (Peer-reviewed scientific discussion should go in Laboratory section). Tips, mouse lag, display lag, game engine lag, network lag, whole input lag chain, VSYNC OFF vs VSYNC ON, and more! Input Lag Articles on Blur Busters.
I have a 5090 fe and 27aqdp and can confirm that the issue is monitors input interface limited to to HBR3, which is roughly 26gbps ... half of what is needed for 2k x 480hz