In 365 you can just ban users from signing up to apps of their own volition. Instead they have the option to request access from admins and then we get that. Surely there is a similar feature in Gsuite
Yeah Google has it too. Yeah you can block unconfigured third party apps and require admin approval for the rest. We just enabled it after we did the audit. problem is it only stops new sign ups, but those that were already connected we have to manually review each grant and revoking what we dont recognize.