Your way will not work because the anonymous users would end up on the login page of your IdP.
I would start thinking about what your home page should look like. I would create a home page that is also visible for anonymous users and have a login button that redirects your regular users to your SSO login page. This way you can split your regular users towards their own home page after login and your anonymous users can do their thing from the public open home page.
Regards,
Ronald