Intermittent fasting is the easiest way to limit total calorie consumption, for most people. It's also a good sort of cold-turkey method to break habits like snack addiction. I feel like our bodies are sort of meant or designed to go without food for certain periods of time; I always feel a lot of mental clarity when I do something like time restricted eating.
Cardio can be great solely because it's probably the easiest form of physical activity to get into and form habits. All you need is a pair of shoes.
Alejandro Kirk if you are reading this, do whatever it is that you can stick to, man.