You gotta be kidding me.
I decided I'm not taking my new (used) phone, the Nexus 5x with LineageOS and my regular SIM card, to the hospital with me. I bought a prepaid SIM, and I still have the old ASUS, which is not a bad phone. I figured I'll use it without signing in to a Google account and install my apps from F-Droid and Yalp Store. Except, that doesn't work. I reset the phone, disabled as much spyware as I could, downloaded F-Droid, tried to install - nope. I thought, well, maybe I disabled too many apps or screwed something else up, so I did another factory reset. Still nope. I had
to sign in to a Google account before it would let me install third-party apps.