Using Firefox mobile, everything works and is mostly performance 🤷‍♂️

You're going to connect to the seedbox at some point, which ties your IP to the traffic. If you are worried about a VPN attaching your IP to traffic, this is no different, no?

If you are worried about VPN's, why are you not worried about seedbox providers?

The OP ruled out zig and rust already

Right, that's what I meant when I said "third party apps". Samsung can write an app to do this, but your average app installed from the play store likely cannot.

I'm not super well versed in the world of app development, but I would assume due to the way apps are sandboxed, this isn't something that could be done with a third party app.

I know it's of very little help, but I have not seen this issue, and I've been using Deluge for years (not automated via the arr suite, however)

It would do you well to find out what error it is throwing (check logs). Would be much easier to diagnose if you knew the actual issue.

im a big fan of the nas device being single purpose. its life should only exist in fileserving. i have several redundant nas devices and then a big ol app server.

This is the way. Except my "big ol' app server" is an n95 mini pc that sips power.

Because even if an attacker could gain access even as root he cannot modify system files.

Your comment was already from the position of if an attacker could gain root access. My responses were to that directly, and nothing else.

Your comment also contained

The filesystem itself is also read-only.

Which is what led to the further discussion of root making that not so.

I don't believe that to be the intent of the OP's comment, given their second sentence, but they are welcome to state otherwise. I just don't want them thinking that an immutable distribution gives them some kind of bulletproof security that it doesn't.

While you are correct, any system is compromised if you have root, so isn’t that irrelevant at that point?

The original context for the comment chain was:

Because even if an attacker could gain access even as root he cannot modify system files.

So no, it's completely relevant.