1. I would recommend #Amethyst, it supports multiple accounts.

2. You say this is vulnerable, but this is a VERY public space.

The only thing protecting you is your nym. Your note is both public and transportable. I can take it and post anywhere, keep a copy, collect your notes, and they are all signed, so although this looks and feels like a small community, don't share vulnerable things here without a good level of nym protection.

Nostr is the most free, unlocked form of publishing in the world. I can repost your messages as Emails, Facebook posts, whatever and since they are signed, it can span any platform. Now the typical user isn't going to care or acknowledge this, but if the reason you wouldn't post this anywhere else is because of a certain person or type of person, consider whether they would care.

They might see a screenshot and believe it, but you can deny it, say it was doctored, and you might even say it if they saw a signed note if they have no idea what a signed note is or how to check it. But eventually they might get wise. If they do, you can't deny it any longer.