AngWay it's just a shot in the dark, but it also might just be Verizon shenanigans. If possible, see if a relative would lend their SIM card, preferably from a different provider. Might be the combination of:
Verizon - GOS
Verizon - Google Pixel
Provisioning profile being broken on Pixels.
As far as I am aware, cellular providers can actively throttle hotspot traffic (since it's visible as hotspot traffic to them). Maybe that wasn't the case on the Samsung, for some reason. I would at least test with a different SIM before taking other, more invasive measures.