After going through this exercise recently I went for the Buzzrack BC3 from roofbox. Really solidly built with tilting mechanism for £190.
BUZZCRUISER 3
Clearance really depends on how close your towball is to the back of the car, some are quite close, others with swan necks extend further from the bumper.
I’ve only used the rack with two bikes, if these are mounted furthest from the doors (VW T5 barn doors (what else !)) no problem opening. But if they are mounted with maximum clearance between the bikes one nearest the door and one furthest away only the door at the saddle end will open.
However if I slacked the towball mount the whole assembly can be swivelled slightly and both doors can be opened but only one at a time.
Forgot to mention the rack locks to the towball and the arms that hold the bikes also have locking mechanisms.