No apple app

Hello!

Can someone please tell me why I am unable to get the Apple Watch app on my new iPhone?! I have already unpair it from my old 6s plus but each time I try downloading the app on my Xs max it’s saying that I should disable the restriction on apps in my settings but the restriction is not enable.... I need help to download this Apple Watch app on my device. It’s a series 2 watch I don’t know if that should be a complication since it’s a older version watch.