Definitely sounds like a USA specific issue. In Australia we pay for GBs data, it’s up to us what we use it on. I’d be appalled if they tried to pull that bullshit here.

Most carriers include ‘unlimited’ data, usually broken up in XXXGb at full speed, then unlimited data at much lower speeds.

Precisely this. Sync was Reddit for me. Now, Sync is Lemmy for me.