How do I stay in a deficit without giving myself an eating disorder? How do I stop gaining the weight back?

I'm 245 lbs 5'11" 20F. this is the heaviest I've ever been. I've dieted for months at a time before, getting to 180 lbs, 10 away from my goal weight and then I gave up and gained it back. I've lost upwards of 40 pounds at a time just to gain even more back. I've sometimes fell into eating way less than what is healthy or obsessing over calories and crying and punishing myself for eating. ive had a weight loss journey almost every year for the last 7 years, just to be the same weight or heavier the next year on January first. I have chronic back pain from a spinal fusion surgery I had at 11 so sometimes its hard for me to get to the gym or even stand for long enough to cook. I know the extra weight is making the pain worse and I really want to feel better. how do I stop gaining the weight? I always have something happen that stresses me out and makes me quit CICO like finals or my grandma that I live with recently got sick and has been in the hospital. is there ways to make it easier so I dont have to think as much about it when I'm not feeling good? is there low effort recipies you keep in rotation for the days youre not feeling 100%?