New iPad asking for really old iPad passcode that I don't have and isn't listed as a device on iCloud
I recently bought a new iPad (A16).
I've set this up as a brand new iPad and not restored from any iCloud backup.
The iPad is perfectly usable which is great, however, I can't seem to fully sign in to iCloud in the settings as it's asking me to confirm the passcode for my really old iPad (haven't had one since 2020).
This device isn't listed in my devices on iCloud (the only device on the is my new iPad).
It's not listed on the Find My app either.
I know my password for iCloud and can log into that perfectly fine. It's still linked to the same email address that I've used for years and would have been used for my old iPad.
In this case, how can I get iCloud working properly on my new iPad when I do not remember what passcode I used for an old device 6 years ago, which isn't even linked to my account any more (at least from what I can see anywhere).
Help much appreciated.
iPad, iPadOS 26