Every instance is good because every instance can interact with many other instances with comments, posts etc. So you arent really locked into one instance. its the magic of federation.
I'd be very careful with those words given that lemmy.world is rather trigger happy with defederations.
It is almost impossible to completely censor away content and anyone can bridge blocks by creating a new intermediary instance where they can view content of mutually blocked instances but it's not like you see all the fediverse content on any instance.
Matter of fact you just need to look at the blocklists of most instances to get a pretty good guess at the other, less legal, Fediverse out there running almost in parallel to the popular one. But since almost every instance has those blocked you don't see any of that shit in your feeds. Highly censorship resistant, but ultimately an individual is still at the mercy of their instance admins.
You’ve just got to make a new account on a different instance. Several of the apps make it easy to switch between multiple accounts on different instances.