Thanks to anyone who's tried to help out, I appreciate it, really I do. I love the phone plan I have at PM and do not wish to leave.
@TE I'll ask that if you're still interested in testing, could you please perform the steps I've outlined in the first post to the letter. It really is the only way to prove out my theory. You started out correct, then just needed to continue at Step 4. (step 4.5 probably doesn't need to be done).
Since posting this thread I've exchanged the first 4a I had with Google under warranty and the new device performs exactly the same, so my current theory is that it's designed this way and the data connection will remain on for some set period of time until the operating system quietly turns it off, probably when the phone is idle long enough. I've described it to Google and they didn't have a problem exchanging the phone.
have you tried the astrophotography mode
Sounds neat. But can this astrophoto thing calculate your exact position (or time) by looking at the stars?
A version of it is included in my GrapheneOS build. But since I installed a modded version of this modded OS on a non-Google non-Pixel device (a Cat S61) my stellar photography seems to default on interesting but meaningless thermal imaging, lol.