Have multiple users for your DB per action?

I installed my mariaDB and phpMyAdmin. I created a new user with all the Grand and Super priveleges. And I deleted the "root" user for savety. Perfect. As I follow an article: make a diffrent user for writing, a diffrent user for deleting, and so on. All for your website to use. Perfect. Than, when set and ready: do not have a userAccount who can do everything and anything for savety reasons. So I removed some priveleges for my new Grand Super User. **Oh oh, I ticked the wrong box** and now my Grand Super User can't see all the other users and can't create new users anymore. And now I am lost in logic. My DB is now handicaped as I can not toy around anymore with adding users and other settings. Now, *I believe*, I need to delete and install a new mariaDB on my Linux just to get **a** database back where I am in control. Am I now understanding correcly that for security reasons; it's best to have a userAccount for every single option, from creating new Users to adding an ellement to a table? And to give arbitrary names to all these userAccounts so not outsider(hacker) who sees these userAccounts gets any wiser?? Or am I completly missing the ball?