My Pixel nerfs itself whenever I cross the border into an unsupported country. Stuff just stops working like Wifi Calling whenever you add a local SIM (and yes the bands are supported). I have to use Pixel IMS just to enable basic stuff. Also forget about 5G (same scénario with the bands). Google will not enable stuff because it's not in their list of carriers. Not an issue with Samsung.
Discussion
Weird. I travel everywhere and never had an issue switching to local sims . 🤔
You just haven’t noticed it before. Google refuses to allow a proper generic carrier support for some reason. Maybe so they don’t get sued by whatever countries version of the FCC. For example +Movil in Panama, Liberty in CR, Tigo in Guatemala. None of them work aside from basic LTE. No VoLTE nothing.