@Saravanan : If users are created in QuickSight, then they would login using username and password.
If users are created in google workspace , then they would login in google workspace and federate into QuickSight. If it is an SP initiated flow , then opening the quicksight link would reroute them to google workspace link, they login and are redirected back to QuickSight.
In this scenario, the user created in QuickSight is different than the user federating from google workspace.
Kind Regards,
Koushik