Tried to add a Yubikey 2FA, locked myself out of my account

I tried to add a Yubikey 5 C NFC as a 2FA login for my 1password account. It seemed to work, but with errors. Now, when I try to log into 1password.com, it requires the security key, but then says “No Credentials Found : No credentials were found for "1password.com" on this security key. Try again with a different security key.” Since this is my only security key, that’s a bit of a problem.

Further, the browser extensions in both Firefox Nightly and Chrome go into infinite loops of trying to request the key and then reloading until I start typing my master password. Once I enter that, it asks for a key. When I insert and activate the Yubikey, the site says “You’re using a security key that’s not registered with this website”. The same thing happens if I try the NFC activation after scanning the QR code with my iPhone. I can’t tell which version(s) of the extension I have because trying to open it from the browser toolbar leads it to also loop between being open and requiring a login.

I seem to still be able to open 1password 7 on my Mac, but don’t know how long that will last, nor how to use it to register the Yubikey with 1password.

So, how do I fix this?

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1Password Version: 7.9.11
Extension Version: Not known (see above)
OS Version: macOS 14.4.1
Browser: Firefox Nightly and Chrome