Diet must reflect what you want, be it massing (building muscle) or cutting (losing fat).
The overall picture matters but typically the main ingredient for hypertrophy is training volume (sets+reps). Training volume is you're trying to progress. You should still get stronger, but you'll be working in higher rep ranges most of the time. It's not ideal to increasing training volume continuously all year long, there will be times to back off but volume is the key variable for body comp.

Diet must reflect what you want, be it massing (building muscle) or cutting (losing fat).
Load is the most important component in strength training or powerlifting. If improved strength is a priority over body composition then you will need to be working with heavy weight in lower repetitions. I would consider technique a close second. Not only does perfect technique place you in the best position to avoid injury but it makes lifting heavier things easier. If you hold a gallon of milk against your belly vs having your arms fully extended it's significantly lighter. Thats what you're trying to accomplish with improved movement patterns.

As for performance. You need your training to reflect what you're trying to perform. Improving your deadlift substantially probably won't help you much if you're a dancer, it would probably make you a much worse dancer. If you're a sprinter you wouldn't become better at sprinting by jogging marathons, you would in turn sprint slower. Practice what you want to be good at.

An individuals goal matters here. I personally view cardio as a performance enhancer. If you can't do 3 sets of 15 with a moderate weight for squats without getting gassed you could benefit from some high intensity cardio. If you lose breath walking up stairs, cardio will benefit you. If your sport requires running then you should probably run.
If you're doing any form of strength training, most people are going to hope to build muscle in the process. Cardio isn't much help here. It may even be counter productive in terms of growing lean muscle tissue. Whatever time you would've spent running on a treadmill for an hour, shift that hour towards your diet or combine that hour into diet/strength training. Muscle tissue looks leaner than fat tissue. If muscle is not much concern and you simply want to get weight off or be super skinny, then go for it with the hours of cardio.

I don't perform much cardio with clients at the gym unless they fall into the getting winded too easy crowd.

For adherence, if you simply like cardio...then do it.

If I ask you "Did you work out this weekend?" and you say "I walked" then the correct answer would've been "No". If you go to Crowders Mountain and walk up to Kings Pinnacle then sure, that counts for something. If you walked your dog around the block instead of sitting on the couch watching Netflix theres really no difference.
If your goal is to lose weight, build muscle and gain strength and all you do is walk, nothing is going to happen. Walking is easy and rarely does anything come easy. Unless you walk around Disney 3 days in a row for 15 hours your body won't need recovery.

Walk because you enjoy it. If your goal is to drop 20lbs in 3 months and you're main source of exercise is walking at a leisurely place twice a week for 30 minutes, up the energy output SIGNIFICANTLY!

I'm not saying walking is bad by any means but it's not much of a goal crusher, it's not the strongest tool you could be using.

For most people, you have full control over what you get out of diet and exercise assuming no significant medical conditions. Great effort will yield positive results, laziness and excuses will result in plateaus, regressions, or total failures. Very few things in life allow an individual that much control.
If you have no will power and blame everyone else for your short comings, you likely won't get very far towards whatever goal you hope to obtain. You're defeated before you start. If you acknowledge your faults you can work to address them. If others are to blame for your own lack of success...well... you'll always be perfect and have no reason to change.

If you're not where you want to be today then something likely needs to be altered somewhere along the way.

Be realistic with yourself. How much are you willing to dedicate or sacrifice towards your goal?
Is meal prep out of the question? Then abs are out of the question for most people. If you're unwilling to track your energy intake then your goals should reflect that. You should strive for modest and minor improvements.

If you strive for substantial fitness achievements be it body composition or performance than you should expect to increase your hours in the gym each week, remove cheats from the diet, meal prep, sleep 8-10 hours per day, prioritize your own fitness lifestyle over your social lifestyle, etc.

If you're willing to put the amount of work somewhere in between those two examples, what you hope to achieve should also fall somewhere in between those two examples.