You body begins to die a painful but probably mercifully quick death. Hormones are vital to your bodies continual survival and even if you targeted specific ones, you’d just be creating problems for yourself. Elimated dopamine? Congrats you’ve given yourself ADHD and a host of other personality problems. Melotonin? Oops no more sleep for you, enjoy your sudden weight gain and compromised immune system. We don’t take hormones, we are hormones.
It’s not an easy transition. My partner works for DDG and I still don’t use it all the time. To their credit they are working to improve things but it’s a small team (comparatively). Their browser has some good features like app tracking protection just from having it installed and quick throwaway email support but isn’t quite up to Firefox’s standard (yet).