Let me start by stating our now-deceased 18 pound Maine Coon, Boswell, used to shed in clumps, requiring a tranquilizer and near-shaving to cure. He would not tolerate more than light brushing even when mat free. Then, our vet lent us one of these:
And I bought a pair of these:
Which allowed two things. First, more frequent, lighter brushings, so fewer mats to remove. And, second, the cat could 'fight back' without damage, which to him was very satisfying.
Sadly we lost him at 16 to cancer. But the incumbents now are also long-hairs but have been trained since kittens to tolerate, in one case enjoy, brushing. But the oven-mitt does prevent excessive emotional reaction damage, no injury or stress on the cat or the servant doing the brushing.