It would be best if this is handled by a particular role where one can still set global filters without being an Administrator or a System Manager.
Let us know if this makes sense so we can take a look and create a PR. For anyone who also wants to pitch in some pointers on where to look and what to check/watch out, then please feel free to do so.
It sounds interesting, on the same lines, providing all the Users the functionality to mark Filters as global can also prove to be chaotic, think about it and please raise this as a Feature Request on GitHub.
I’ve been trying to save filters as global both as Administrator and System Manager but this checkbox is unclickable on my self-hosted instance. I’ve looked into the code that @creamdory linked in his post and in my instance everything is the same in this code, yet I can’t save Filter as Global. Any advice?