good man, weight training has been proven time and time again to be far more effective, if done properly. A good weight based circuit will burn cals, and if you get your body into the right hormonal state will also focus on fat first, especially with high intensity weight based workouts. Fueling your body the correct way afterwards is also critical.
As you get to your 40+ you need to focus on muscle to help prevent a lot of ailments (it's been proven to help reduce the chances of osteoporosis for example) as you get older, cardio is still important but that can happen without running - you just need to balance it. a HIIT workout is far more effective, and you can do it with weights and even compound movements.
Muscle maintaining is the name of the game as you get older rather than pure building of muscle. Something I've discovered - although someone in the gym rats post did say they wished they looked like me despite them being in their 20s!
It's taken 20+ years of good eating and building a base to prevent #dadbod, you have to be committed and you have to make it a lifestyle choice.
However lean muscle gain even in your 20s is a long term thing, it's actually quite hard to do, but in your 40+ with lower testosterone levels, it's going to be nigh on impossible, so you're better off focussing on muscle development, which at 40+ is going to be slow anyway, and focus on good dietary choices.
I think you mentioned it as well a ratio of fat, protein and carbs. Personally, I'm on 40% protein, 30% fats, 30% carbs, that works for me, but I'm also eating 3.5k cals daily
My lifestyle choices have meant that I hardly eat poor foods. I literally only eat boringly good foods now, but it's the choice I've made and my blood profile is spot on for my age, and in my opinion I'm in pretty good shape - it does take effort. I don't drink alcohol, or milk, and hardly have any sugary foods. It's not for everyone, but I feel 10 years younger than I am.
It's in everyone's gift to do it, but it's not an overnight thing - and that's what people find difficult - the effort, and it's mentally really hard too.