In time, things settle. Those that defederate too much will soon become self-isolated and that's totally fine. Most of the servers will remain federated and will be the body that everyone wants to connect with and others may be very happy to self-isolate and not caring about any other servers or their communities.

What I do find possible is that the owners of federated servers will start to form a governing "council" that share some agreed principles for content and the allied servers would all defederate from any server that violates their shared content rules. To join the main group, you have to agree to abide by the council rules or be defederated as well (for example a server asks to join the main group, then also feds with a piracy server on the group ban list, so it gets defederated by the group).

I feel like NSFW stuff will be fine here, but the questionable, non-consensual stuff will not even be visible by the main group. The federated servers will be the content core, the unfederated servers will be like the wild west, full of questionable and potentially dangerous stuff.

Just give it some time, this is sudden and unexpected growth. It's healthy. I think people are starting to see just how corporate social media is, and how much they are both the content generators as well as the content consumers. So steps to take back the control of how we communicate is a win for us.