Templates for custom fields
Instead of having to type out every single label and its text contents, why not have an option of creating custom text box templates with labels and even contents set by the user? For example, an user might want to know which of their accounts utilize their external 2FA security key. With this feature added, they'd just have to click Edit > Add more > Select field template, after which they'd have a field named "Utilizes security key" for which they'd then have to select a binary answer of "Yes" or "No"; Or, they could select a template named "Phone number" in whose text box they could write a Google Voice number specific to that account.
It would be also helpful to have an option to add any custom field to any credentials by default, meaning less time spent clicking through menus.