When I do push-ups, I often shift my focus to the side with less strength, and it will be balanced after a long time.

But doing sit-ups is not necessary, but your abdominal muscles will naturally balance when they are stronger.

Sometimes the muscles will be very painful after exercise, which will inhibit your perseverance in exercise. I suggest you buy some analgesic aerosol (preferably Yunnan Baiyao aerosol). Spray it after exercise.

The muscles on your right side are well developed, which is probably related to habits.