When I served in the military, my first supervisor taught me a valuable lesson: "15 minutes early, or you're late." I actually got in trouble with her if I was less than 15 minutes early to any meeting, appointment, or event.
Or even arriving to work. We worked in an IT field, so our office had a large row of server racks along one wall. Her desk sat facing the door, but next to the GPS server that kept accurate time for all our computers on the military base. It had a giant digital clock on the front of the server. Every day when I walked into work, she would look up at me, then turn and look at that clock. If I was even 10 seconds late (to the 15-minute rule), I got in trouble with her. I was never late to work though, because she ensured I was always there earlier than my official shift start time.
Being 15 minutes early to everything has changed my life. If I'm running behind, I have a quarter hour window to get myself back on track. If I arrive 15 minutes early, I have plenty of time to get myself set up and situated. Or just time to sit and clear out some other pending tasks while I wait for a thing to start (check phone notifications, clear out emails, etc.).
When it comes to virtual meetings, I like to join 15 minutes early, then mute myself and turn off my camera. Then I can sit at my computer and knock out some other tasks while I'm waiting for the meeting to start. That buffer gives me time to mentally switch into meeting mode while also giving me time to be productive beforehand. And no one is waiting for me to show up, so if the meeting is ever running late, it's never my fault.