> Amazon prompts me to create a passkey everytime I log in, even when I logged in with a passkey, because my passkeys live in Bitwarden rather than my OS or browser.

I use 1Password and Amazon does not prompt me like that. However I do have two passkeys for Amazon, one in 1Password and one in Apple Passwords. There's not enough data yet to say if it happens to you because of something not working right between Bitwarden and Amazon, or something about Amazon doesn't work right if you don't have a passkey in your OS passkey store.

Might be worth adding a passkey for Amazon to your OS passkey store and see if the problem goes away. If it does, blame Amazon. If it does not, report it as a possible bug in Bitwarden (altough it still could be an Amazon bug that just happens to mess with Bitwarden but not 1Password).