The best advice for new and inexperienced riders I could give would be to get comfortable on a bicycle

It might sound either obvious or counter productive depending on your views but if you're looking to get onto a motorbike and have any doubts about your CBT or mod 1 test - get on your push bike.

Get familiar with riding as slowly as you can, get used to the feeling of the minor steering adjustments you have to make, how sitting upright Vs leaning forwards affects your balance, practice leaning into corners and swerving around an open space.

Try to ride along painted white lines and dodge stones on the floor etc. All things that transfer to riding something powered by an engine rather than pedals.

Yes, a motorbike is way heavier. But you might be surprised how much of an advantage it will put you at - especially before you commit to spending money on a CBT or further.