Sharepoint SPSE and oidc with identity server failing

Hi Andrea Dal Farra, sorry to hear that you're having difficulty getting OIDC configured successfully with your identity provider. Unfortunately this isn't enough information for us to go on to investigate this issue.  We'd need to understand what your repro steps were, your full ULS logs, and a capture of the looping requests in Fiddler or similar web debugging tools.

I recommend opening a support case with Microsoft Support so they can work with you to collect this information and pass it on to the SharePoint team for investigation.