SSO works great but we need Forms authentication for a single dashboard / app

Product: PowerShell Universal
Version: 3.8.12 and 4.1.8

We use windows auth (sso) on our production server and this works great so far. But now we need to create a single dashboard / app that will use form based authentication. This dashboard will be accessed on domain joined computers but kiosk style, so a shared user account is used to login to these computers. We do not want this shared user account to access the dashboard - but it should be possible to login to the dashboard with other windows credentials.

Is this possible, and if yes … how do we go about this? I have found some forum posts etc with something similar but it seems to me that they don’t have windows auth SSO setup. In any case, I can’t get it to work, so any help is greatly appreciated.