Many people have been arrested by the surveillance state recently due to their lack of shielding online regarding protesting activities. There are many things that can be done to alleviate this, regarding different apps. Before anything, however, you need to designate yourself a pseudonym to use in antifascist circles. Example: JC (Junior Comrade)
Never, ever associate yourself or your real name with protests unless you are there clearly designated as press. Always use your pseudonym, even in real life.