Redirecting from login

I want my site to redirect after login to site_url(‘/’) for all users except ‘administrator’
I also want the admin_bar showing for certain roles ie event_planner. It is all working except that when and event_planner logs on and then clicks on the admin bar to go into admin it redirects to ‘/’.
The hook being used to redirect is ‘admin_init’ which is clearly wrong.
Is there another hook I could use to initially redirect to / on login but not when pressing the dashboard on the admin bar.

check to see if hook is available

I’m using a theme-specific, custom hook to add some custom attributes/values to the page’s <body> element. There are however pages on my site that use a template that do not have that hook available and for certain reasons, I cannot modify that template or create a custom version in my child theme. I have a less elegant way of adding the attributes/values that I obviously only want to use when absolutely necessary.