21% percent is considered just above what’s called “healthy” which typically falls between 13-19%. However if your looking for a particular physique then that’s different. Most people will have a 6 pack at 10% body fat and that’s why so many people chase single digits.
First, you should figure out what your TDEE is at your 169lbs. Once you do that you need to set up an eating plan for work out days and rest days based on your weekly weight loss goal. At 21%, you can lose up to 1.7lbs per week and not lose much muscle. But macros and nutrients come into play when your attempting to lose that much fat while maintaining muscle. What I’ve seen work while in that big of a deficit is 45% of your cals coming from protein, 40% carbs, and 15% fat on workout days. And then 45% P, 7% C, and 38% fat on rest days. At 1.7lbs a week, that’s 850cals a day deficit.
In all likely hood, your TDEE is some where around 2300. Let’s just say 2350 for math purposes. The average gym goer is goin to burn 600-1000cals in a 1hr work out. So on work days you eat your maintenance, 2350, and on rest days you eat at the 850cal deficit, or 1500 cals.
To get down to 10% you need to lose roughly 20lbs (9kg). At 5’8” 149lbs 10% your going to be cut, but look very small. At some point on the way to 10% this why most people give up. As you drop BF% you’ll have to reduce the amount of weight your attempting to lose per week, 1.5lbs/week, 1.2lbs/week, etc. But if you hit a plateau, you’ll have to drop the calories consumed on workout days by 5%.
Long answer short, you need to buy a scale, a blender, and measuring cups, and a calorie/ macro tracker like MyFitnessPal. It will take roughly 4 months of discipline.
I’d also recommend cutting out alcohol.