This question is especially for people who have joined in the last week. Have you used other fediverse platforms or is this your first time really using one? What do you think of it so far? Are you aware that you can comment on Lemmy posts with a Mastodon account?
I literally just joined about an hour ago, so take my comment with a grain of salt, but maybe you can manually track the communities you sub to on your current instance in case that happens? I did some reading and it seems possible to set up something like an RSS feed for Lemmy communities, so you would still be able to view activity without an account (if you instance goes down), and you have something documenting the communities you are interested in. Sorry if this is not useful, just trying to do my part and be more active here.