Hi all! What a shitty day for me. I potentially screwed up all my privacy efforts to remain as anonymous as possible.
My Pixel with GOS was not tied to my identity during purchase and it's been running on a VPS with permanent killswitch (also not tied to my real identity).
However, today, I stupidly connected my Pixel to my OpenVPN service, hosted at my NAS at home that is tied to my real identity. This connection was for less than 10 minutes and basically connected my device to my NAS domain, which is consequently linked to my identity.
While I am of course not doing anything that would land in me legal trouble as I am an ordinary law-abiding person just trying to improve my digital privacy (ie., my threat model is not high), I supposed I ruined most of my progress with stupid move to make a raw connection from my anonymous device to home.
So I guess my carrier (not tied to my real identity), now has sufficient data to enable an adversary know that my Pixel's IMEI belongs to me and as I connected to my NAS via OpenVPN.