For people who have or had severe long term obesity, and lost the weight using GLP's, stopping it after losing the weight is pretty much wishful thinking. By all means try, especially if you have better eating and exercise patterns, but I think it would be important to restart it sooner rather than later if weight started increasing , otherwise you are basically back to yo yo dieting, which if you stay on them you may never need to do again. I strongly agree with the comment above that if it takes constant mental effort to keep the weight off by eating less than your body tells you to, it is not really sustainable, almost everyone will run out of that sort of effortful mental energy eventually.
For people who are not in this category, ( less severe obesity or more recent ) it is not quite as straightforward , although I think the same issues apply in the end. Putting back on 10 or even 20 kg is not great for health but not anywhere near as destructive as bmi's in the 40's or more. The biggest advantage of GLP drugs is that you can keep the weight off. It does make it a bit easier to lose the weight in the first place, but almost everyone who has any kind of weight problem will have lost some weight successfully at some point, it really is not the hard part. The hard part is months or years after, still having to resist eating things you want to eat, if you do not want to regain the weight. And doing this when stressed or upset or at Christmas or on holidays etc. GLP drugs essentially solve the problem, given that in this weight range they are good enough to get to healthy body weights or non overweight BMI's, and it does not require that constant forever mental effort, just keep taking the GLP, and from what is currently known but not yet proven in healthy populations, they are likely to make you live a longer healthier life. Assuming side effects are not a problem, it really is a no brainer, and if you do not stay on them and put weight back on the chances are you will end up needing blood pressure pills and statins and maybe anti diabetes medications in the long term anyway so you do not necessarily escape relying on medication either way.