You do need root privileges if you want to install font packages so that everyone on the system can use them. If you only have yourself as a user, you can just drop ttf or otf files in an appropriate $HOME subdir.

You can also build yourself a read-only disk image and run overlay, or run NIXos, or guix, or whatever. I find it baffling that you find it desirable to sneer at instructions on how to do things appropriately for the specific system that is being referenced.

Hopefully other people will find some value in what I wrote.