FYI I am a paying Workspace customer. I disabled Gemini retention. Doing so means no chat history sidebar- all are ephemeral. It was org-level. That became impractical. I re-enabled it. Magically, all of my old chats were back. The ones during no retention mode weren’t there. Perhaps if I’d left it off for more than 30 days the old stuff would have been truly removed.

The point is there is no conversation-level controls. It’s incredibly user-hostile.

This sounds like a news worthy observation, to me. That Google doesn't delete your data when you ask to.