I was registered on lemme.ee. Has this instance ceased to exist? TY.

Yes, a while ago. There was a month warning for people to move their accounts

Ah. I missed that so I'll investigate other instances then... Or just see what communities propagate here.

My account is a year old and I switched from lemm.ee a week or so before it shut down.

Sadly, it looks like it.
Honestly, it's kinda like my own instance... life got in the way and then I just... stopped posting.
So eventually the VM was shut down without me really knowing/paying attention, because I didn't have any monitoring on it.
But from what I can tell, it's one of those things that Lemmy/Mastodon/PubSub as a whole... it's not Reddit, and I think that's where everyone is going to struggle.

Reddit had some bad publicity last year, but I think it'll take a LOT more than what they've done to actually push a majority of people away. I think even those of us that tried to move away... there was just so much established community there and there is certainly a lack of it here :(

All communities propagate everywhere, basically. When a community has even one subscriber from an instance, all of that community's future content will propagate to that instance.