My guess is that small targets like the fediverse will likely escape scrutiny because it would be a lot of trouble for a tiny handful of users.
If large numbers of kids started moving here once all the big platforms are blocked, and the pearl clutchers get wind of it, then the govt might move slowly towards trying to do something.
The two major parties here are always trying to out do each other when it comes to taking away digital rights.
Circa 2009 we had Labor trying to bring in a nationwide filter. That failed however since then we have had a ton of shit legislation with bi partisan support dropped on us.