M1 Macbook Air, on Big Sur, 11.0. Try to sign in with my Apple ID, get to the point where it asks me to enter the passcode for one of my other devices. It shows me my iPad and my iPhone; if I select either one, and enter the correct passcode (and the passcode has never changed on either device, and I definitely have it correct, confirmed on the devices), it hangs for a while and then says the passcode didn't match. Eventually gives me a "too many times" error.
I'm not the "first" user on the device, if that makes any difference (my wife is) - but I'm an administrator.
Other than updating (which I will probably do), is there anything I should do to get around this? It's not the end of the world, but keychain doesn't sync, which is a big pain.