Can't access old device because of two factor authentication
I have an old Ipad 2 I just dusted off. Some years back I gave it to my kids to play with and one of them put a passcode on it which noone can remember anymore. I still have my phone number as my two factor authentication and I used iTunes from my PC to reset the ipad but I can't set it up. Whenever I log in with my AppleID it first asks me for a code from a sms which I supply. Then it thinks alot and asks me for a code from my other apple device. I should mention that I don't own any other apple device. If I put in the only passcode I know ( 0000 ) it tells me I cannot use the passcode for the current device. Si when I log into appleid.apple.com I can see that the ipad has added itself as a two factor authentication device and is asking me for a passcode to itself which it then won't accept because it's the same device.
I can still use my applid on this site and in iTunes on my PC just fine. I just can't use it on the ipad.
I'm at a loss - I feel like apple isn't doing a very good job with it's two factor authentication method here which leaves me with an unusable device because I don't own another apple device? It makes no sense to me. Any help would be greatly appreciated.
iPad 2