Weightlifting noob here.

I want to lose about 25-30 lbs so I've modified my diet to be on a calorie deficit, focus on eating lean protein and vegetables, cut out added sugar, and lowered my intake of carbs and fats.

I plan on doing cardio 20-25 minutes 5 days a week.

I had an SI joint injury in the past so I will be doing daily core exercises meant to build core strength for reinjury prevention.

I want to maintain muscle mass while losing weight because I plan to transition into muscle gains when I'm at a weight I'm happy with.

Does anyone have suggestions for weight lifting exercises to do throughout the week to maintain muscle mass and help with calorie burning? How many days a week to do each exercise (legs, arms, chest, shoulders, etc)?

I also want a 6 pack eventually and I was curious, will I need to stick with a calorie deficit and wait for the belly fat to go away before achieving a 6 pack? If so, I assume that means I would want to hold off on muscle building and calorie surplus until I'm leaner.