I don’t think it’s possible. iTunes requires a full OS install, so you’ll have to just run it on a VM. And Apple has things locked down so much that the only way to do full iPhone/iPad backups is through iTunes.
I also wanted something like this, but I don’t want every single community. I ended up making a not account that I use to subscribe to random communities I might have a fleeting interest in, but don’t want in my subscribed feed.
A gentleman never gets cheaper. He just doesn’t immediately raise his prices to keep up with inflation.