The GNU GPL, BSD license, MIT...those are so last century. Today we have many other cool licenses to use and you should definitely switch all your code to one of these.
HOT POTATO LICENSE
Version 2, September 2021
All rights reserved by the last person to commit a change to this
repository, except for the right to commit changes to this repository,
which is hereby granted to all inhabitants of the Milky Way Galaxy for
the purpose of committing changes to this repository.
A really important thing to remember with all licenses is that they're only as useful as your ability to enforce them... in court. And there's a non-zero chance that at least some of these are practically unenforceable anyways.