The very first video in the original post shows the UFO coming to a dead stop and then rotating around its vertical axis, which is very drone-like behaviour, and I think it rules out a fixed wing if they are all a coordinated stunt.It doesn't necessarily have to be a drone. What about a large RC fixed wing model? That's what it looks like to me. A fixed wing model doing turns, rolls and dives.
The model in this video has LEDs all over the place, but the object in the OP videos looks as if it were a model with LEDs in the wings only. The wings "change length" as the model turns.
Usually less noisy than drones. There are RC models with 4, 6, 8 foot wingspans. So something larger and farther away will be quieter still.
The classic how big/how far away in the night sky problem.
Would also explain why a desultory search in the dark of night didn't turn up any operator. The operator of a large RC airplane could be hundreds of yards away even if the model were almost overhead.