I watched a bit of it before (sorry, I'm just one of those people -_-)
When you mentioned the rust in the video that's a really bad sign considering it's going to be kept in a moderate to high humidity which means substantial rust.
Them telling you to just clean it off is a seriously bad sign.
Scratched tubs are pretty bad (I could have lived with them but whatever)
Not being able to remove the ventilation sheets looked pretty annoying.
Now, the castors being that difficult to put on could have been a good sign (new nuts and bolts can be difficult), but there were too many other red flags in there.
Did you happen to order a discounted used rack? Because with the rust and the scratches, and the vents it looked like a used rack.
Oh lord... video 2 of the vent sheet was absolutely terrible. That build quality is a lot less than I would expect for something that runs with those price tags.
Personally I would suggest reptile basics racks. If it turns out you can get an equal amount of tubs for less cost, I personally recommend their pre-built racks