Global Oppo Find N5/N6 + TMO & VZW. Possible?

I am drooling over Oppo's foldables and lamenting the loss of OnePlus. It should be possible to activate with TMO with no issue, and I think VZW by activating on a supported phone with a sim, and dropping the sim into the Oppo phone.

What I don't know and would appreciate:

- How frequent are VZW sweeps to detect and disconnect unsupported phones from network?

- I care about coverage, not gigabit speeds. I need min 8mbit to do my work. I travel quite a bit and don't want to lose out on common channels from both VZW + TMO.

- I don't necessarily care about high density mmwave.

Has anybody had success stories doing this? Any recommendations?