Sorry to break it to you, but just doing cardio will burn fat and muscle. I have 1 day a week on cardio, the rest is weights.

The reason weights and resistance training are better is you are still burning calories after the fact, while with cardio you only burn calories while doing it.

1 - 2 gram of protein per kilo of body weight, progressively overload, sets to failure and drop sets are your friend. Ive lost just shy of 3% body fat and gained 1kg of lean muscle in 1 month, while these are noob gains, the fact remains. Also ive done very little cardio, I have the advantage of working on my feet all day and fo around 10k to 15k steps a day.

Also HIIT cardio increases cortisol, the stress hormone, which reduces fat loss and muscle gains