I forget but I think someone in the Linux sphere set up lemmy sites as a distinct unit for download on apt or kde or snap or something. Might be worth looking into.

Supposedly once you're hosting sites it's easy to set it up as a tor service in some setting or other, but I imagine federation afterward to be a bit of a challenge. It would have to fit the activitypub protocol or whatever it is and I'm not sure how to make that work over such a gap.

Running Lemmy it's pretty easy. Setup some containers. Unless you plan to open registration but keep the instance only for yourself (like I do), there is really no more maintenance needed.

Probably you don't even need a server in itself, a PC that stay turned on most of the day will work just fine, data exchange between federated instances will resume then your Lemmy is online

Maybe update the containers periodically and check that disk usage doesn't grow too much, but that's up to which and how many communities you subscribe to, since you are the only user of the instance.