i just use pacman, mean it has checksum tests after downloading since youre only really downloading the launcher

im stupid

i only ever used arch linux idk how other distributions handle it

try installing ffmpegthumbnailer and see if that works after reboot / relogin, if not uninstall and try another method

american cultural imperialism is pretty prevalent in the western world. everyone known american music, wears american clothes (jeans), speaks english, has american military bases etc