The display on my laptop is 4k and i can tell you i tried downscaling it was not as big a difference as simply turning the brightness down as low as was comfortable.

maybe a silly question bit is mint using pulse audio?

i unfortunately using kinoite for my desktop and Debian for my servers. I am not totally in love with kinoite but I don’t dislike it enough to change back to regular fedora.

you can use grub-mkconfig to verify the grub config and rebuild it if necessary. i dont recall the exact syntax for your distro so I would look it up first.

I am not positive but if it still true originally webos was not linux. It started off as a very ahead of its time cell phone os made by Palm Inc. After they failed to gain traction it was sold to LG or made open source then sold or bought. LG uses it in their TVs but if I recall the base os is not Linux but some form of palmos assuming it has not been moved to Linux.

Display port does not have audio