Deploying Microsoft Defender for Identity

Your screenshot showing adding the GMSA account seems to be missing the $ the docs state to use when adding a GMSA account to the portal?

https://learn.microsoft.com/en-us/defender-for-identity/deploy/create-directory-service-account-gmsa#configure-a-directory-service-account-in-microsoft-defender-xdr 

You should also add  you must ensure you give the GMSA Account read permissions to the AD Recycle bin as outlined here - https://learn.microsoft.com/en-us/defender-for-identity/deploy/create-directory-service-account-gmsa#grant-required-dsa-permissions