Sure, deep analysis of my usage, connection, browser user agent, browser fingerprinting, etc could reveal who I am and that information can all be correlated if requested by Government agencies although my privacy isn't completely surrendered on an alt/fake name account.

I have a Facebook account primarily for Market Place under a completely fake name. I very rarely comment on things on Facebook, but it feels good knowing that my real name is not being posted. From a glance, Meta cannot confirm this account is owed by Joe Blogs.