Hopefully you guys got it working but for anybody still struggling, this should work. Last year i used the 'OTP at the end of the password' trick, but unlike rklurfeld, the only method that worked for me this time was using an authenticator app (i.e. Google/Microsoft Authenticator) and my regular login. Sorry this is so wordy but I work in IT and find that some people need things explained in depth or they end up more frustrated than when they started.
In Amazon, go to account settings → Login & security → To the right of '2-factor (2SV) settings,' tap 'Edit'. I can't remember the exact steps but you'll be given a 'setup code'. Copy it → Go back to your Authenticator, hit '+' to add an entry and choose 'use setup code' → Pick a name, enter the code we got from Amazon & choose ’time based' **A 6-digit code will be under 'Amazon' but they're only good for a min or two so we're not ready to copy it yet → Go back to synchronization settings in Deliveries & choose Amazon under 'External' → Remove current account if previously linked → Enter Amazon username/password, select a sync period then tap 'OK' → Go back to Authenticator, tap+hold the 6-digit code shown under Amazon and return to Deliveries → Paste the code you copied from Authenticator into the Deliveries pop-up and watch the synchroliciousness!