OP doesn’t seem to have responded, so no, but that’s not the fault of the question.

Because of the XY problem. The problem OP is stating may not actually be the source of the issues OP is experiencing.

Finding out what OP is trying to do will better inform a solution and may make the stated problem irrelevant.

When I initially set up my media server I went with Jellyfin over Plex mostly because the idea of having to create an account on an external service to use software I was hosting myself rubbed me the wrong way. Since then the more learn about Plex the more baffled I am that anyone chooses to use it at all.

I wouldn’t buy a new Seagate drive, let alone a refurbished one. Every Seagate I’ve ever owned died in less than five years. Every WD I’ve owned lasted until long after their capacity was so far outpaced by newer drives as to be useless.

Anecdotal, yes, but it’s happened enough to me that I’ve been soured on them for life.

Same setup here, two USB drives dangling from my NUC. One of them is even notably slow for a USB drive. Still not an issue at all for home use. I’d probably need a dozen or more people all watching different things on Jellyfin at the same time before it even approached being a problem.

The difference between building your own car and designing your own internal combustion engine.

That tracks with my experience as well. Literally every single Seagate drive I’ve owned has died, while I have decade old WDs that are still trucking along with zero errors. I decided a while back that I was never touching Seagate again.

There isn’t much difference at all. Neither should have a cap.

Data moving across a network doesn’t have any per-unit cost to the people operating the network. Whether you use 5TB or 5GB doesn’t impact the bottom line of the ISPs at all.

The only justification for a data cap would be if they’ve overprovisioned their network and sold too many people plans that are too fast for their network to support, so they need to disincentivise people from actually using it. Even then that’s pretty shaky justification.