Hey Beryyk, the best way to improve your fitness level so you can do more exercise is with high intensity interval training. HITT will really improve your endurance and also help your body utilize fat for energy too.
Try this quick HIIT circuit:
30 seconds jumping jacks or jump rope
30 seconds plank knee-ins
30 seconds running in place
30 seconds walking lunges
30 seconds dumbbell or resistance bands rows
30 seconds mountain climbers or hip thrusts
30 seconds
Check out my
high intensity interval training guide for more tips and ideas.