Two things:

Sadly, my USB port completely borked, so that’s off the table. I use KDE-something-or-other to txfr files over my internetless wifi.

Second, I did look into it, and even on my Graphene OS phone, the USB tether is treated identically to the hot spot; that is to say, the carrier can detect you’re connecting a device and there is no workaround other than paying the cellular provider for the privilege of using your connection as they see fit.

The only hassle is the tranfer, and that’s set & forget.

And I don’t spend $50-100/mo (wifi + streaming)to waste time channel surfin.

I’m using Cricket wireless. $45/mo gets me unlimited internet on my phone with a 15gig hotspot.

I’m all physical media, but if I need to download something, I do it on my phone (sorry, seeders) and transfer it over to my PC to watch on my TV.