Are these posts and comments permanent or is there some type of expiration date?

I only ask because I've noticed more than 3 posts are either hidden or gone. I'm assuming I haven't already got banned in some way, but I'm also kinda confused how this lemmy federation crap works. Can I sub to non-monero lemmy communities with this profile or do I have to host my own instance to do that? sorry for being smolbrain