All of these are “root” mounts. I don’t explicitly mount any subvolumes (they get “implicitly” mounted as folders though)

Just let some bees loose on your system for a while and they’ll sort that out.
Also depending on how good your CPU is btrfs compression would also save a fair bit. AFAIK shared libraries are pretty well compressible.

It’s possible by having the webfinger endpoints at the “root” while keeping the rest of Lemmy on a subdomain. The main thing that determines the domain in your username is webfinger.

No clue if Lemmy or kbin support this config though, but quite a bit of the microblog-only parts of fedi do, and it’s a widely used thing.

jsyk, with how ActivityPub works changing the software that’s running from under it will break federation with you in all sorts of subtle ways. When you pick a thing to run under a domain you’re effectively locked into running that software under that domain. And of course there is some cryptographic verification as well so you change the keys (or you wipe or forget to back up the database) you may as well burn that domain from federating ever again.

On a desktop or especially laptop case, it should be equal to (or larger than) your RAM if you use hibernation (as RAM gets copied to swap during hibernation)

On my server, I set it up to be 2GBs, mostly arbitrarily. Right now it’s at 500MB, but my main memory is also only 600-800MB full out of the total 4GBs available, so I’m not running out of RAM anytime soon.

Swap behavior seems to have changed a while ago, so consider reading https://chrisdown.name/2018/01/02/in-defence-of-swap.html on how it works right now. Hell, even that might be outdated nowadays. Up to date info on how swap works really seems hard to come by.

Moreover I also have my swappiness set to 0 because I don’t want stuff swapped out of memory. If I need more memory I need more memory.

I don’t think swappiness has worked that way for a while now.

https://chrisdown.name/2018/01/02/in-defence-of-swap.html