Set up an alternative 2FA method, log in to the iOS app on your iPad using the alternative 2FA method, and subsequently try to log in again on the iOS app on your iPad using the Yubikey (source).
Instead of a USB-A to Lightning adapter, try this USB-A to USB-C adapter, or perhaps something equivalent (source).
i do have other 2FA option set up - Authenticator app.
There is no option to login with this option though in any of the screens I’ve been through 50 times.
It gives me that option if I try to login via a webpage from ipad, but not thru the app.
That seems odd. What about when you login to the iOS app on your iPhone instead of your iPad? Do you see the option for choosing alternative 2FA methods? Are you using the same version of the iOS app on your iPhone and on your iPad?
I’ve wasted so many hours on this, (this isn’t my first issue with BW either). I just signed up for a different password manager. Quick, seamless, 2FA, everything works. So much easier.