I don't really know much about how Lemmy works under-the-hood, but from my previous experience with running Akkoma and Mastodon instances, you can have your instance subscribe to a relay to have messages from other instances pushed to yours. They're only really useful for smaller (<1,000 users) instances.
In this context, since I don't know if Lemmy instances can be subscribed to a relay (I don't see why not since it is ActivityPub under-the-hood after all), I'm not entire sure.
Cinnamon on Manjaro.
Yes, I know using Manjaro is cheating, but I could not be arsed to set up a DE by hand for the upteenth time. Manjaro Cinnamon ISO go *brrrrrrrr*