Every system I design has this "impersonation" feature, and none of them have any capability for surveilling usage. It's just a way for me to see what my customers are seeing. Helps me understand their problems, bugs in my system, etc.

I have direct access to all the prod databases and lots of tools for inspection/auditing. This isn't for that. It's for helping people by seeing/using the system through their eyes.

It ideally doesn't need to be a privacy-invading thing, but rather a way for administrators troubleshoot issues a bit easier without having to get on a screensharing call. I think maybe what makes it difficult is that Gmail might be used as the key to authenticate into other accounts (like for shadow IT).

And in the ideal case, even this action that a Google Workspace administrator logged in as someone else would be automatically written into an audit trail.

Impersonation is not what you seem to think it is.