[dredmorbius]

Yeah, but that's mostly useful to law enforcement, if they were interested

De-anonymization has been studied and applied by various parties, and I'm personally aware of at least one non-LEO application. I don't know that Google does or doesn't do this, though it wouldn't surprise me at all if marketing/advertising and/or other "personalization" services did. It would annoy me intensely to find that they were.

For that the mere fact of a cell phone is enough to get everything you mentioned.

A dumb phone can only report coarse location information, SMS messaging, and calls data. Frequently expiring SIMs would limit the useful duration of much of that information, though you'd need something like a self-hosted Google Voice forwarding service to be able to use the phone usefully while maintaining reasonable anonymity. It's not currently practical for most purposes.

Relying on a Free Software VOIP service based on the tablet preferentially for voice calls would further reduce exposure.