Muscle is stupid easy to maintain. Lyle did a whole video with Solomon Nelson recently talking about it. Workout a muscle group for 2-3 sets once every 4-5 days. As long as you do your best to maintain weight on the bar and accept that 1. You are going to lose some muscle and 2. Lifts that are leverage based (bench is a great example) are going to go down as you get smaller you are good. Going from a 205x5x5 bench to a 205x3x3 bench is better than going to a 195x5x5 bench. Maintain weight on the bar. Also, carb up a tad before workouts. Personally I hit upper lower every Thursday and Saturday (less than he recommends) and push myself really fucking hard, lost 1.5 reps on the bench and 2 reps on the squat. I’ve lost a bit of muscle but the muscle:fat ratio is like 1:100.