This does not refute your bonus point, because this is going to depend on who you are. In my experience, though, when I am exercising, yes I may eat a bit more to replace what was spent, but I’m also put in touch with my body a bit more, and get clearer signals for what to eat. This often ends up becoming a kind of feedback loop, because I’ll start craving healthier foods that contain more micros, are whole foods and are less dense. I’m no longer eating just to get through, but responding to my body intuitively, which significantly reduces the cognitive load of “gotta eat healthy foods”.

For example, maybe I’ll want a chopped up head of iceberg lettuce with shredded beets/carrots, SMALL portion of chicken/salmon/tofu and a piece of fruit instead of just that dense protein bar or bag of chips to keep me going. Good luck gaining weight on the first one - you would literally not have enough time in the day to prepare, eat and digest an amount that would add any weight.

Exercise doesn’t have to be crazy strenuous either. Just moving at all helps, and low impact movement can help tremendously with the aches and pains that can come with extra weight. OP is very young, and might not be feeling it yet, but she will.

Walking, swimming, cycling, and yoga are all fantastic places to start out, and those activities do have varying levels of accessibility but they’re still all very achievable for the vast majority of people.

CICO is fundamental science, but there’s also human psychology and the brain-gut connection to contend with. Anything which could result in compounding effects to accelerate and complement your strategy is worth trying IMO.