Anyone have a rec for a simple LTE phone that works with Google Fi that I can basically use as a Wifi hotspot?

I know the data-only SIMs don't support tethering, so I assume that means I need the main SIM with a real phone. I'm just looking for a cheap way to use that main SIM as a hotspot.

I'd buy just an LTE MiFi if anyone knows for sure that a main Fi SIM will work in it and allow tethering.