How do I keep my feet on my pedals?

Heavy feet first and foremost, your weight should be coming down into the bottom bracket through your feet.
Feet coming off the pedals is generally a sign that you have the weight of your body in your hands.

Second, forming a wedge with your feet is helpful. Your front foot while riding should have a dropped ankle, and your rear foot should be pushing back against the pedal slightly with your toes slightly dipped down on that foot. This forms a bracing wedge.

Finally, proper pedals and shoes do help, but unless your weight is actually through your feet, even the most velociraptor spikes on your pedals isn’t going to save you.

looked like you got compressed coming into the drop and then didn’t really have any weight on your feet during takeoff. Overall it looks like the bike is in control here and you’re just along for the ride.

Try getting really good at dropping off curbs and small stuff. Learn how to land both tires at the same time, rear tire first, front tire first. just really become a pro at dropping 2 foot curbs before you go bigger. often times pushing the limits too far too fast actually results in bad technique because you end up survival riding instead of riding with confidence.