This is a rear question, but sometime your organization may require to control the security of entire SharePoint online site and disallow default "Everyone", "Everyone Except External Users" or "Allusers" to be used by respective site owners.
Currently, it is not possible to disable this group from office 365 tenant but you can hide this group to be visible so that when site owners are providing permissions to users on SharePoint online site, they actually can't see or search it.
You can use below PowerShell command to hide this group:
Set-SPOTenant -ShowEveryoneExceptExternalUsersClaim $false -ShowEveryoneClaim $false -ShowAllUsersClaim $false
For more information, you can refer below article: https://docs.microsoft.com/en-us/powershell/module/sharepoint-online/set-spotenant?view=sharepoint-ps
What will happen to exiting SharePoint online sites (after you hide this group)?
It won’t effect those currently using "Everyone", "Everyone Except External Users" or "Allusers" claims. However, if site owner delete Everyone (for example) from the members group, they will not be able to re-add it because it won’t show up in the people picker. (Unless you set that parameter back to $true for the entire tenant.)