Here's a random data point.
My parent's flight today was delayed 2.5 hours by not enough crew. Then they leave the gate, have to return due to mechanical. Then the mechanical issue is fixed but they have to go back to the gate and reboard everyone because two people left during the mechanical repairs and something something security / manifest / etc.
Left 4 hours 59 minutes late... half of it sitting on the plane. On the ATL -> SFO flights today, 1 of 7 cancelled, 1 of 7 had a 5 hours delay. Not great.