This is not possible in SharePoint.
The SharePoint Site Collection Administrator cannot be locked out of any subsite, list, library, item, or page on the site.
The permissions inheritance for any of these elements can be broken at any time, and permissions changed so that even users with Full Control rights have lesser permissions or even no permissions at all.
In all cases the SharePoint Site Collection Administrator will always have full access to all of the elements and all of the data. This is especially handy when a site Owner accidentally deletes their own user account or group when creating custom permissions!
Source: What Is a SharePoint Site Collection Administrator?
The only possible solution is to update the site collection administrators so that they are populated with users that you do want to be able to access the whole site (i.e. the business/IT users who are the only ones who should have that access).
You can grant Full Control/Owners permissions to other users if needed.
Update from comments:
It is must to have at least one/primary site collection administrator on a site.