Funnily enough, I find the opposite. In person play is characterized by a lot of gaffing around time and no one ever playing in character.
Whereas online play features virtually zero gaffing around time and players will stay in character far better.
I noticed something similar. When we played online during covid, there was lot less joking around. But it's mostly cause we were all at home, with wives and kids around. Can't really go all out like we do when we are in person and alone (no SO, no kids, we can let loose our inner teenage boys crude humor). Also, it was, at least for my group, harder to focus on the game. Every session, at least one of us had to take brake or two ( diaper duty, help out wife, or put kid to bed etc, family stuff). We even tried late evening sessions from 21 till midnight, but around 22:30 everyone was on autopilot and half asleep.
In person, sure, we joke more, have more side conversations, but that's what makes it fun, at least for me and my group. For us, playing d&d is first and foremost form of social gathering, spending time alone with friends, have break from adulting. Game itself is just medium that enables it, shared activity. Some play football, some go to bar, we play d&d.