Major problem with 2FA and Yubikey

Hello moonpup! 👋

I'm sorry that you're running into issues with authentication when adding your new account to the 1Password for Mac app. The old account suggestion that you're seeing in the 1Password app on your Mac is being shown because the 1Password app has found that 1Password account in your iCloud Keychain. In order to make it easier to sign into your 1Password account on your Apple devices 1Password will store an encrypted copy of the equivalent of your Emergency Kit in the iCloud Keychain.

If you have an account being found in the details stored in iCloud, and you no longer want that account to show in the list of found accounts, you can remove the data from iCloud keychain using these steps:

1. On the Mac, launch the "Keychain Access" utility that comes with macOS. If you see a prompt asking you to manage your passwords in System Settings, click “Open Keychain Access”.
2. In the search box in the upper-right corner of the app, search for "com.agilebits.onepassword.b5" (without the quote marks)
3. Each search result you see is one account's details that are stored in iCloud Keychain
4. Double-click on the entry you want to examine
5. Tick the "Show password" box at the bottom of the Attributes tab, and enter your macOS user password when prompted
6. The contents of the box will show the stored account details - you can click into the box and use the up and down keys on your keyboard to see all of the details
7. When you have identified the entry that relates to the specific membership you no longer want to have recorded in iCloud Keychain, delete that one com.agilebits.onepassword.b5Credentials entry

So I select my new account to use Yubikey by clicking the key icon in the upper right, and when it asks me to tap the key

This definitely isn't right and we do have a known issue where security keys registered using Firefox can fail to work with the desktop app. Our developers are investigating. If you used Firefox to register the security keys then can you remove them from your 1Password account and try to use a different browser like Safari or Chrome to register the keys?

Let me know if they work once you've done that.

-Dave

ref: dev/core/core#27958