Cardio for 20-30 minutes daily will shift the body towards fat metabolism at a cellular level via changes in gene expression, but it will also slow down the rate of protein synthesis (muscle building). That being said, single bouts of cardio will ONLY upregulate glucose transporters so it's really important to be consistent in your training if you want to see a full body transformation.
What I did to get from 15% BF to 6.5% in 8 weeks without supplements was the following:
1. Decrease caloric intake 10% below TDEE (find a calculator online if you're not sure)
2. Take in 220 cals of fruit before every workout
3. 30 mins cardio after lifting (I lift 6 days a week)... I've also found that biking was better than running for keeping muscle on
4. No cheat meals, high protein, no fancy diet... just my normal 35% carbs, 35% fat, 30% protein... tried to carb cycle but only got severe insomnia
The idea being to keep high protein and lifting to prevent muscle breakdown. The preworkout carbs were there to prevent me from going into cardio with depleted muscle glycogen stores (which would again favor muscle breakdown). I just gave my body time to increase fat metabolism on its own and all I did was try to prevent it from breaking down muscle. It worked for me and I'm just a normal guy.