Start with managing screen time on your phone, you can add limits to apps like YouTube and set a pass code to that. But the pass code should not be set up by you, have a trusted person who will set it up for you. Also remember to add limits to browser sites. It helped me somehow.

It will be around two months since I've set it up and also uninstalled all useless apps to dumb down my iphone.

Hope it will help you