You can have Home page per role.
When the user logs in, based on the role he has, he can see the particular home page.
Runtime must not always start from the login page. If you want, you can create a different page for Anonymous user role and show that as default. And then you can create custom login button on that page which would take you to the login screen.
I would also recommend going through
to get a hold of various concepts of mendix.
Go in learning path and type in search “Custom Login”, hope you will get what you need, and select the 1st result i.e 3.4 Custom Login Page