Yes this works on many instances. I believe some instances even have a dedicated community for this but I can’t remember any right now… I think if you search for “support” communities each instance pretty much has one and you can request to take over a community whos mod is inactive.
Related question: is there any procedure for taking over an abandoned community?
My understanding is instance admins can change moderators, so depends on the instance the community is hosted on.
Yes this works on many instances. I believe some instances even have a dedicated community for this but I can’t remember any right now… I think if you search for “support” communities each instance pretty much has one and you can request to take over a community whos mod is inactive.