You can probably sneak up on those matts & just work on them little by little. Keep some brushes & scissors by the lounge so when you are cuddling you can sneak a little grooming in. Yes, if you snip those matts through vertically, you can gently teaste them out & they are less likely to reappear that if you chop them off horizontally.

Sonny never got matts in his ears until the vet cut the hair there when he was looking for a suspected tick. It took about 6 months before those matts stopped forming.

I use a slicker brush & just start brushing from the bottom of the matt, & then as it starts to loosen up, work upwards.