I think you are asking: From which hubs and with which airlines and on what days of the week is there likely to be more overhead bin space, even if I board in a late boarding group?

Weekends are nuts to and from CUN, especially as we move into the high season. I'm beginning to wonder, though, how low the low season is anymore. Tourist figures to Cancun and the Riviera Maya have more than rebounded from their pre-pandemic levels. Tourism is booming all year, except during the height of hurricane season in the fall. Flights are full.

Here's what it comes down to me: If you have to gate check your bag, you do it. You can't predict in advance what will happen if you board in a late group. You make sure anything you need during the flight and cannot afford to lose (money, credit cards, wallet, medications) stays with you. You pick up your bag at baggage claim on arrival. CUN airport has greatly streamlined immigration procedures on arrival with the e-gates and the elimination of the tourist card requirement for many visitors. That's the good part. Baggage claim is the same old bottleneck it always was, though.