RLS + Embed Link. How can i use RLS with PBI email&pass auth to access a report outside PBI Service?

Hello everyone, hope you're doing well.

I have a client that wants to use Power BI Reports on his on application. The way we're approaching right now is basically creating a share link for the reports and then he adds this link to his application - which works well for reports that doesn't require RLS.

But now came the day that he needs to limit some users access data using RLS. He wants that the report consumers could access the report from inside his app and use the already autenticated e-mail and pass from microsoft account to consider the RLS roles.

The question is, how can i do that? Because when i create RLS roles, the embed link option desappears. Also, the reversal, if i try to check which user is logged in accessing the report using USERPRINCIPALNAME() with a shared link, the return is NULL, ie. accessing the web shared report though the shared link doesn't capture the user logged by standard.

Thanks in advance for your support.

Stay safe.