I’m very uncomfortable using DMs that don’t have forward secrecy. That builds up a growing trove of private message history that will all be revealed if your key is ever compromised, increasing the potential harm with every message.

Just add an expiration tag to your gift wraps and/or use a DM relay that only you can download them and that it allows you to delete these events in whatever schedule you want. It's much easier for users than dealing with secondary keys for DMs that can't be saved on Nostr because if you do, you lose all the forward secrecy gains.