When it comes to exercise, there is a big difference between how a bodybuilder and an athlete trains. The first is more concerned with aesthetics, while the latter is concerned with the ability to move and compete in their discipline.
If you are looking to improve your appearance, lift weights and eat a high protein low sugar low salt diet. Strength training is superior to cardio in changing the way you look.
If you want functional strength and endurance, do bodyweight calisthenics, cardio, and eat a moderately low carb diet, with more carbs on the days you are more physically active.
Since I never desired to look good when I was young, I never lifted serious weights. Matt Furey’s book Combat Conditioning was very influential on me because it taught three simple bodyweight exercises as the core of what you do to get athletically ready for contest. Every other exercise is just a peripheral.
My favorite cardio is what is easiest, which is walking, something everybody knows how to do.
There is one big flaw with bodyweight exercises without any equipment. And that is, it is hard to recreate pulling motions without doing pullups on a bar. Without training the pulling muscles of the back and just doing pushups, squats, and back bridges, this creates an imbalanced body and a slouching posture, something that has happened to me.
I suggest going as old school and retro as possible, doing cardio outdoors and doing your calisthenics in the park. As long as you are doing natural exercise and you spice up your routine with variety, you will get fit without much effort.