Dropping body fat %

I'm also trying to change my composition. To spare lean mass the main idea is to still be at a caloric deficit but getting plenty of protein (around 30%) and keep strength training. It's tough. Good luck!

Progressive lifting proven program. Eat enough protein (1gr per pound of lean mass). Slight calorie deficit. Profit.

Going from 22% to 15% shouldn't be too difficult (as compared to getting to extremely low bf %s i mean).

in fact, even just living your daily life while at a calorie deficit, should almost completely achieve that with minimal lean mass loss.

But to speed up the body fat % drop (not all weight loss, but by gaining a little muscle at the same time, would change the fat to lean mass % quicker)
High protein.
Strength training 2-4 times / week depending on your routine.
and don't have too severe of a calorie deficit. The more severe it is, the more likely (or larger proportion of) muscle mass will be lost. @ 22% 500-750 calorie deficit should be safe enough.
Although as you get close to 15%, maybe reduce the deficit by a small amount.

And of course, rest days are important. Stress will increase lean mass lost and just make weight loss more difficult than it needs to be. And I mean all types of stress. Mental/emotional stress from normal daily life. And also nervous system stress and strain from strength training. + muscles need 1-2 days to recover and grow between workouts anyway