But how can admins take ownership of a team or give it to an existing user when the original owner is no longer part of the organisation (account removed) and teams show no owner at all?
Only an Owner of a resource (File/Project/Team) can transfer its ownership. Please note that the term Owner only refers to the creator of the resource. Being an Owner of a resource does not grant you any more privileges than an Admin or an Editor. Admins and Editors on a resource should still be able to carry any administrative tasks the Owner can.
Since the Owner is no longer an employee, I suggest having an Admin remove the user. When an Admin removes someone, we will:
Immediately remove their access
Prevent the user from accessing teams, files or libraries
Remove the user from every team they own. From there, the Team Admin(s) will be able to carry out any administrative tasks on the team. If there are no Team Admins, an Org Admin will be able to claim the team from theirAdmin Settings > Teamstab(teams can be filtered byTeams without owners). (More info here:Org Admins claiming ownership of teams)
Still provide existing Editors access to the user’s Files and Projects while they are ownerless.
Move the contents of their Drafts to the organization’s Shared Projects folder. (More on that here:Managed drafts of deleted Member)