>>25591533
That's not how it works, stop spreading boomer memes. It's only a matter of controlling exertion, if you can't that's your skill issue
>>25591559
>25-30 bf
That's a lot. I suppose you are aware that you also need to change your diet, not only exercise.
>default position
Do you mean with feet relatively close together? And if you can't squat with them shoulder width despite not carrying any weight then you definitely have mobility issues. Do you feel pain when you try that? If it is only discomfort but not pain you should do it regularly to increase mobility, like stretching. And then you should also lift (ensuring you always do the full range of motion) and do cardio, at this point your main concern should be your health and not how optimal your routine will be muscle ananolism wise. But like I said before you definitely need to change your diet too so you need to decide if you are willing to do that first since it's the most important factor.
What about your rest? What time do you go to sleep and for how long? Do you drink coffee at night or anything like that?
>>25591567
Marathon running is very specific and not what most people do when they say they go running. If you are that much into cardio you might want to check hyrox
>>25591583
Martial arts are great cardio but it might be better for OP to fix his health issues first. I've never heard of someone incapable of squatting their bodyweight.
>>25591592
Modern BBs use more drugs and breathe like a pug. If you want a famous recent example Sam Sulek split his cardio in 2 or 3 parts during his recent cut because he couldn't do a single convenient cardio session.