Any tips on dematting cats?

[Marthe48]

I have a long-haired Manx kittie. She is about 16 years old, and has always been queen-sized. My late boy cat would groom her head and neck, and she was not as messy overall. Now that she's older, it is a constant battle to keep her from matting. I have 3 different kinds of brushes and a rake. I brush her several time a day and rake her at least once a day, but she keeps matting. I've been cutting her sides the last few days. My goal is to get her hair as short as I can get it, especially the problem areas. She doesn't like the scissors, so I do a little at a time. I've never snipped her skin, but she acts like I'm killing her. I read you aren't supposed to cut mats, but her hips get pretty matted and she doesn't like me to brush her hips. Last night, I held her in my lap and gently pulled the mats to seperate the hair. She didn't like that, but our session lasted longer than cutting and brushing. I keep bacon bits on hand, and give her a few as a reward, especially after a tough session.

I give her a butt bath about once a week. I imagine that even if she isn't messy, the bacteria is irritating. I feel like she is letting me know when she wants a bath, because she'll follow me to the bathroom and gets a certain look. She protests, but tolerates the bath. And she gets a treat afterward.

I won't ever have a long-haired cat again. She is a really good cat, and since she's become an only cat, her personality is really showing.

If anyone can advise on keeping her from matting, many thanks!