No first hand experience, but during Covid TP web or app wouldn't allow you to generate a BP. You were able to check-in (OLCI) but the BP had to be collected at the check-in counters due to Covid documents check. It may have changed by now - or it may be the same; I guess you will find out when you do OLCI.

I would assume TP check-in counters to open 3 hours before departure, but again no first hand experience with SFO.