Whatever these UAP are, they are most likely unmanned . They pull too many Gs for a biological entity to survive. That one video said the UAP dropped 80,000 feet in about a second. That can also be written as 54,545 miles per hour, or mach 72. We currently can fly mach 9.6. In an 80,000 foot dive, the G forces would be astronomical. A normal person blacks out at 6 G.
Unless alien biology is solid state, no living thing is in those craft. It could be robotic or remote controlled. Insects can survive 200-400G, so maybe an insectoid pilot would work, but at 80,000ft/sec they are being pushed past that point.
I've always thought UAP were some kind of probes. They aren't terrestrial, at least not from any current nation. There's no chance the Russians or Chinese have this tech and the USA does not.
They could be holographic projections, so not really objects existing in 3-dimensional space, which would mean the physics in their flight (e.g., no propulsion system, no external steering valences, stopping on a dime, body-exploding g-force acceleration) are the wrong idea. They could be a 3-d representation of a 4-d construct.
They could be solid objects (not holograms) that are using gravitational holes to move. So they aren't really flying like a jet plane but are more or less popping in and out of our space-time.
Even less likely, but maybe more fun, is they could be probes sent back via wormhole from a future civilization, us or extraterrestrial. That explains why they sometimes crash, they observe a lot of military things, and no one seems to know where they come from.
Due to the insane distances between stars, biological entities in crafts is the least likely explanation. It would take 200,000 years at light speed to cross our galaxy from tip to tip, let alone get to the next galaxy over. So if they are biological they are from the Milky Way. If they come from Andromeda, that's 2.5 million years to get there traveling at light speed, forget about time dilation. The closest star system is Alpha Centauri at 4 years away, traveling at light speed. These aliens would have to be so superannuated that 8 years spent on a trip to earth would be nothing. So these craft cannot possibly be piloted by living things.