So apparently nip46 is a thing, and the Amber app has it, but as a 'remote' signing function, I've searched but haven't found any #nostr client that supports this.
The closest thing I've come across that uses this function and flow (Amber on my phone: tap QR scan -> scan QR on my PC (or on a separate phone app) -> authorize -> done. Then I'd start getting push notifications to authorize events, adjust settings, etc) is this site: https://smartvaults.dev/
However, its specifically using their own app so Amber doesn't work with it.
Demo: