Sometimes enabling Full Composition Pipeline can resolve Nvidia-related display issues, including brightness, gamma, and flickering.
In your case, you have hybrid graphics, and I’m assuming it defaults to the AMD GPU unless you’re gaming or doing GPU-intensive work?
However, what you’re describing (such as the inverted hotkeys to increase/decrease the backlight; but “reversed”) sounds like the HP laptop’s hardware is built exclusively for Windows 11, and if you can get Linux to work on it they don’t care either way. (As is evident by any desktop environment of any distro, even from a live ISO.)