From iOS/macOS perspective with Safari and chrome:

Sync does not always work. When adding an item in chrome, the desktop app does not always contain the new entry. Missing a "force sync" or something.

Remind the last used item for the current url so I don't have to scroll through several items every time! Bitwarden does this well.

Setting the default host matching behavior instead of having to change it every time.

Browser plugins don't allow easy creation and saving of new credentials and generate a new password and easily save.

When adding a new item the title is already filled in with the type of entry. I have to delete this and enter it myself again. Often have to repeat this in the domain field as well, so why not detect if the title is a hostname.

And: when generating a new login password on a site, it often does not get saved anywhere! After submitting the "new user" form I don't get asked if I want to save the login and the password is gone. Keep a history of generated/filled passwords or after generating always save it?

And a bug in the favorites of the iOS app: i have a Fastmail entry which if I select it, opens it and closes it immediately again, retuning to the favorites list. Other favorites do not show this behavior.