I think this one section from the legal documents will answer your questions:
Legal - Apple Media Services - Apple
M. "Family Sharing Rules: You can only belong to one (1) Family at a time, and may join any Family no more than twice per year. You can change the Apple Account you associate with a Family no more than once every ninety (90) days. All Family members must share the same Home Country."
So, if you need to change country you have to leave your current Family group. You cannot be part of it and have your account set to a different region. You are limited as to how frequently you can join the family. Even if you wanted to leave the family, change country for a bit to, say, download an app or two in the other country, you would then have to change country again and also be limited by how many times per year you could do that. Furthermore, read the support article Change your Apple Account country or region - Apple Support which describes how to change your country setting on everything using your Apple Account, and the requirements and results of doing this. As you can see, changing country is no trivial thing to do and not a way to get around the Family Sharing restrictions.