The badges and notifications can be turned on and off for the APP in settings, but not for individual email accounts within the app for a single logged in Mac user. This is also true for the apps for iPhones, for instance.
Apple even calls these icons APP ICONS, there is a single one for each APP, but not for each email account when a user has multiple such email accounts.
Apple's solution (which may or may not work for you) would be to create new user accounts on the Mac for the other users whose emails you currently receive email for. Then you would have them log into their user accounts on the Mac to see emails and email status. Your email account would the only one for you in your Mac user login, so you would no longer see a badge count of messages that includes their unread emails.
This can be fast because you can have fast user switching to switch quickly between Mac user accounts to access each one's emails, all can stay logged in.
I use both Outlook and Apple Mail and neither can show a badge notification that includes info for one email account but not the others when one single Mac user has multiple email accounts. The badge notification is for the app and all the email accounts that the logged in user accesses for that app.