For an app to remember user credentials, is Native Datastore required?

Hi, trying to figure out why our Safari web app works perfect with iOS Passwords/Keychain for remembering login credentials, and suggesting strong passwords, etc, but with our Median iPhone app, the same login screen accessed through the Median app doesn't seem to recognize our domain and work as expected. Is it because we need to setup Universal Links or a URL Scheme or add a Native Plugin like the Native Datastore? Really not looking to add biometric or Auth0, just looking for a user/pass text integration with iOS Passwords/Keychain that works for our Median app like it does when accessed through the web on mobile or desktop. Guidance appreciated! Thank you!