> For me, this commitment to geographical, language-based spaces is in contradiction to what attracts me to the internet in the first place.

Seconded. And, with regard to the Estonian Mastodon instance, "communities" created in that way seem to be created to enhance feelings of national pride and identity. Even if it is done to promote the use of Estonian language, it's exploitability for (and by) nationalist causes speasks against pursuing this path.