Getting list of all site collection admins for OneDrive
Currently, there no way to fetch a list of all site collection admins of all OneDrive account. The only way to check it is by going to Admin Portal and checking it for each and every user.
PowerShell (Set-SPOUser) allows to add new site collection admins to SharePoint sites and OneDrive. However, Get-SPOUser doesn't get the site collection admins unless the admin account is already site collection admin on the OneDrive.
It would be great to have some way for admins to fetch a list of all site collection admins either using script or GUI.