@simsa04 I don't really know if all fediverse projects have been contacted or have responded to address group compatibility. I'm guessing that the ones which have, will see some sort of inter-operation.
Besides that, yes, it was a bit of a rant about Mastodon, that keeps adding "features" (sometimes they are, sometimes not) and the rest of the fediverse have to keep up... if they can. It is a bad scenario, if you ask me.