zerodawn
The arrs would be your best bet to reduce your input. If i’m not mistaken you can run them all through docker including a version of qbittorrentb that’s bound to a vpn and the only way it access the internet is through that vpn. Or you could split tunnel your vpn and bind your qbittorrent to it and bipass your jellyfin instance.
I can’t speak on anything with beeper but a similar service that is self hostable is matrix-synapse. I mention self hosting as an answer to your concerns of safety but the other side of the coin is this isn’t introductory stuff, if you don’t have a background or general enterpris experience with this kind of thing i don’t recommend it. If you do then this seems like a good fit as you can run your own bridges into the matrix service you’re hosting so all your data stays on your own systems.
If i remember correct the vm i’m running lemmy on has less than 300gigs of storage and i’ve used less than half of that with running lemmy for a couple of months with a hand full of users. I can’t speak to the bandwidth aspect but i’d imagine self hosting lemmy would almost be better suited for low bandwidth so it can pull down the posts over time and hold them locally for you when you’re ready, but thats just a guess.