Welcome to Discourse Meta @Encounter 
An admin who owns/created the forum cannot be ‘demoted’ as their email is in DISCOURSE_DEVELOPER_EMAILS inside app.yml.
If you are self hosted and don’t want other admins getting demoted just add them to the developer emails and do a rebuild.
You could also explain to other admins not to demote others if you don’t want to make changes to developer emails. As a side note… As you’d expect being an admin is a powerful position, and ideally you don’t want many people with those privileges.
If you wanted to change the shield colour of admins and moderators to help differentiate them, you can have a look at this guide:
You can also use titles. For example the admin who owns the community could be given an ‘owner’ title so that everyone knows who not to demote if that is what you are worried about?
Hope this helps 