What could be the reason that an unused app is unstopable and not as unused deactivated

If I am not mistaken the Samsung watch app does not generally work on custom ROMs and probably less so on a non-Google setup.
Keeping an app that cannot be used and is causing problems doesn’t seem to make much sense.

That said, there is a post here with a method to get the app (Galaxy Wear?) working without root.
Maybe see if it will work for you.