I'm on hybrid, but my entire team is all over the world, so I'm just as alone in the office as at home. The only difference is that in the office I'm bound by the train schedule, so I can't take out of hours calls. My coworkers and manager keep petitioning HR to let me work from home full time.
We have access cards to unlock the office doors; this is tracked. Everyone is required to be in the office for a certain amount of days per month, and a monthly report is always generated. I found when the fewest people are coming (nobody on my floor), and that's when I come in, given that my entire team are digital nomads, so I'd communicate with them via Slack anyway.