I think on mutable distros, or at least arch, you can run a command to reinstall all installed packages, which will verify integrity of the package files (signatures) and then ensure the files in the filesystem match package files? And I think it takes minutes at most, at least for typical setups.
I do think it's also possible to just verify integrity of all files installed from a package, but I don't remember if it required an external utility, pretty sure it's on the arch wiki under pacman/tips and tricks
2025 will truly be the year of the Linux desktop! I am so happy about this information!