I'm unable to replicate the problem that you describe.
Have you selected just Bitwarden - and deselected iCloud Passwords & Keychain from the list of available password managers?
If the settings are as described, select iCloud Passwords & Keychain - and deselect Bitwarden.
NB: Ensure that you know your Bitwarden Master Password - as this will be required.
Next, delete the Bitwarden Password Manager App from your iPad. In removing the Bitwarden App from your iPad you won't lose your securely saved credentials - as these are backed-up by the Bitwarden cloud service:
Remove apps from iPad - Apple Support
Now perform a forced restart of your iPad:
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.
Force restart iPad (models with the Home button)
Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
After restarting the iPad, reinstall the Bitwarden Password Manager App from the App Store:
https://apps.apple.com/app/bitwarden-password-manager/id1137397744
When reinstalled, launch the App - and enter your Master Password. Setup the App as required - and verify that your saved credentials have been reloaded. When ready, revisit your iPad's Password settings - and test as necessary.
