Here's my theory:

Nostr will mostly be left alone for some years.

While the EU bureaucrats are largely incompetent, they are still rational enough to focus on practical results.

Their goal is to limit the spread of non-approved opinions, since public perception is still vital to their power.

Since most Eurpeans are not on Nostr, there is low risk for the EU bureaucrats that Nostr will have a great impact on European public opinions in the near future.

If the majority of sheep are not listening to lions speaking the truth, the EU regulators will focus on more pressing matters.

Once that changes, they will certainly try to ban Nostr in the EU.