Who trains beginners in backhand clear/smash technique? It’s an advanced skill.
I never came across anyone on the Junior circuit with a natural backhand clear.
I don’t know what your expectations are of beginner but they’re a lot higher than mine. I’d put them at rules of game, serve, grip, basic strokes, basic movement and positioning. None of these would be expected to be honed in any way.
His grips and strokes are far from perfect, his movement sucks and he’s slow, but he’s positioning himself with some knowledge on the court.
The guy can forehand clear tramline to tramline and backhand clear at least 3/4 to tramline (1.40). He can smash forehand and backhand (6.18), lift, serve, clear drive, drop. It this is a beginner then badminton must be an easy sport.
Just for reference here is a beginner syllabus. There is nothing on backhand or footwork.