Have you read "The Hacker's Diet"? It was written by the guy who founded Autodesk, and I found it very useful. My own weight control system now is a simplified and informal version of the one in the book, I used it to go from over 105kg down to my target weight of 90kg and then sustain that loss (staying between 88kg and 90kg) for most of a decade now. A couple of times I've let it creep up and the same methods got me relatively quickly and painlessly back into range.
The most important thing is to see your calorie intake, not as a goal in itself, but as the control variable in a feedback loop, with your weight as the process variable that you're trying to control. (If you really wanted to get hardcore about it, you could use a PID controller to set your daily calorie intake. :)
When you reach your target weight, keep doing whatever you were doing and just gradually increase your portion size until you stop losing weight. If you're gaining weight again, gradually reduce portion size until you get back to your target weight. If you're losing weight, gradually increase portion size until you get back to your target weight. That's literally all there is to maintaining a target weight.
The most important thing is to see your calorie intake, not as a goal in itself, but as the control variable in a feedback loop, with your weight as the process variable that you're trying to control. (If you really wanted to get hardcore about it, you could use a PID controller to set your daily calorie intake. :)
When you reach your target weight, keep doing whatever you were doing and just gradually increase your portion size until you stop losing weight. If you're gaining weight again, gradually reduce portion size until you get back to your target weight. If you're losing weight, gradually increase portion size until you get back to your target weight. That's literally all there is to maintaining a target weight.
Link: https://www.fourmilab.ch/hackdiet/