One of mine is an angora cross and it’s really difficult to keep him matt free. I actually shave his fur quite short every 2-3 months and it’s much easier to look after. Not shaved right to the skin just short! He has matts appear literally overnight and there are areas which are more prone to it eg under his chin & down towards his front paws, on his sides just at the top of his front paws and behind his head. I find metal toothed combs best for grooming and also slicker brushes if you can find one of the ‘gentler’ ones.
My bunny also had to be fully shaved when he was brought into the rescue, I feel so sorry for him that he was born with such difficult fur as he really doesn’t like being groomed.