Why Apps - Get Reports API not suport service principal

I want get report list and its report url from APP. Then add a button in our site, so user can click button can link to report.   

But this https://learn.microsoft.com/en-us/rest/api/power-bi/apps/get-reports API not support Service principal authentication  

So I try to use this API: https://learn.microsoft.com/en-us/rest/api/power-bi/reports/get-reports-in-group  

But it return report url links to workspace which user don't have permission...

I want use script to fetch reports info, don't want add my personal account into code. 

Is there nay method to fetch report list in APP?