The best solution would be to implement a "learning feature" where form fields can be graphical selected or skipped, to have an internal map for key=>id of the form elements.
I have seen this with another passwortmanager. I cannot remember the app because I've tested a lot (maybe it was Dashlane) and this works great.
Bring this to another level means to have a complete internal map of all key values from Enpass to a id/name of a form element. If there is also some kind of searchlist to allow different id/names (a list with alternative names which can be used in the regular expression to find a matching form element), this opens the door to complete form filling app (and would be amazing)