I wouldn’t bet on it. If the baseband modem has access to location data then it could send it without the OS being able to intervene. I don’t know about Pixels, but many devices are highly integrated now that I would want some real thorough and specific research before I trusted that an OS could block the modem from sending location data.

Nope, any modern modem have gnss builtin, even if you buy say quectel modem now you will have that included and how you can access the location through AT commands. Bottom line: anything that connects to operators tower should be assumed it is tracked.

It is not.