I would have thought that if a complete novice went for 1 weeks holiday they would be doing more by the end of the week if they boarded…… but the learning curve is fairly steep.
Snow conditions make big difference to learning to snowboard. If it’s icy then you could spend quite some time wondering why you bothered.
If you’ve ever skateboarded, wakeboarded, surfed or windsurfed (short board) before, then snowboarding will come easily.
Deffo. after a couple of ski lessons you will be able to get down just about anything, even ice. Not so with a snowboard imho.
Best idea would be to have a crack at both and see what works for you.