Do you use the (new) Nextcloud 31 release? In Nextcloud 31 you can activate in the admin sharing options index.php/settings/admin/sharing (Allow users to set custom share link tokens) the customisation of sharing names. Then you can set the old share name to a new file. If you use Nextcloud 30 or lower check the app Configurable Share Links.
I would have expected the files in team folders to continue to exist without the user and the shares to continue to function. I’ll have to try it out.