It seems like Proton Pass will just use the username instead of the email no matter what, and you can't disable or change preference once it's populated, the only way is to basically delete it and add it to the notes or hidden text. My usecase would be to just have the username there just in case if it's needed and be able to choose which to prefer/prioritize. Sometimes some services will base accounts, security and support on the username (steam, ubisoft) more than they would on the email address, but they still require email (or both) for login.
Buzzeger5
It seems like Proton Pass will just use the username instead of the email no matter what, and you can't disable or change preference once it's populated, the only way is to basically delete it and add it to the notes or hidden text. My usecase would be to just have the username there just in case if it's needed and be able to choose which to prefer/prioritize. Sometimes some services will base accounts, security and support on the username (steam, ubisoft) more than they would on the email address, but they still require email (or both) for login.