Look OP, you’ve been extremely combative and defensive from the start. If you’re like this with your ex it’s hardly a surprise that things between you are acrimonious.
Posters here have seen many, many instances where the dad fucks off to do whatever he wants, only bothering with the child on every other weekend or so. Exactly as you described here. That may not be a fair reflection but objectively, it seems to tick all the boxes.
You claim to have had no choice about moving 100 miles away but that’s nonsense. You chose to move to make your life easier, rather than continuing to commute. Thats on you. In the meantime, the mum is left with the day-to-day grind.
Posters here have tried to explain why a call might feel intrusive. The camera may only be in the spare room but that’s missing the point.
Ideally yes, there would be no issues with you calling your son. And if your ex is just stopping them as a power move then yes, that’s dickish. But it sounds as if this was a particularly acrimonious split and although you’ve tried to paint her as controlling, the incidences you’re describing make you sound pretty controlling yourself. It’s just poor all round.
You say you believe your child is ND but undiagnosed. Most ND folk are better with structure, knowing what’s going to happen and when. Unplanned calls can make them dysregulated - it’s possible that your ex is seeing a fallout after the call. Or your son may find it harder to do other things that evening because of the unplanned call. Multiple things can be true - she may be cutting off the calls just to piss you off, but also, she may be dealing with behaviour you’re unaware of.
In your last post you said that you’re moving back. That’s a positive start. And yes, given that your co-parenting relationship seems to be poor, you’ll have to go through the courts. However, as your child is 14 years old it should be much easier as they get a say in what they want. 50/50 contact should be easily attainable. That would solve the problem, right?
I’m AuDHD myself with ND DC, and I’ve given similar advice to a female friend recently. Focus your energies on getting a practical solution in place - wasting your headspace on bitterness about your ex’s behaviour achieves nothing. You say your move back is imminent so start the ball rolling now with your solicitor. Court action takes time so get started.