Best: use a SSO. Usually Mendix apps are used in companies, most of them have a central IdP and use some sort of SSO to connect only once a day. Go with that for the best user-experience.
This is what we are currently using as best practise.
containes a page, a layout Sass and .html
ap_login 7.23.3 zip found here:
Here our current login screen:
Since you also are using SSO we always provide a button for our SSO customers (this is a multitenancy environment). On that page they need to enter their accountname so we can decide to which SSO config we need to redirect.