I have a tendency to jojo after every successful diet. You probably already know, but (sorry): Stop eating out and put food under your complete control. Other than that:

Don't blame your lack of willpower, there is solid scientific evidence that the tendency to overeat is physiological. Accept it and congratulate yourself for every day you manage to win against your own treacherous body. It's much easier not to gain weight than to lose it, so look at any diet not as a temporary inconvenience but as a candidate "forever" lifestyle change.

Things that have worked for me: limiting my calorie window. I try to wait with the first calorie of the day as long as I can (most days that's 8am, some days I can go until 12) and then stop eating at 4pm. Promotes insulin resistance by creating a window for the body to get started on consuming stored energy instead of busily storing always available ingested calories.

Secondarily, portion control. I drink only tea and black coffee and treat anything else (occasional lattes) as a meal. I count calories. It's tough at the beginning, but once you have done the math on your go-to meals, it becomes much easier. I allow myself anything up to 1200 kcal and then put the brakes on, with the aim to stay under 1800 a day. That's surprisingly little (I find that almost anything I eat comes out to around 600 in practice), but after getting through the initial change, it works. The thing to realize is that calories in/out really matters, but the empowering part of that is that you can actually eat whatever you like as long as you control the total.

Third: supplementation. Contentious, but here's what works for me: I take 1g NAC, 2g physellium husk and 2g Citrulline in pill form; NAC in the morning, and 1g psyllium and Citrulline after every meal. It works to keep my cravings under control, and these substances are typically available in food, I am just upping the concentration to simulate fullness and high protein meals promoting satiation.