There are different ways to check the completed responses:
1. Survey dashboard: Survey >> Analytics>>Dashboard: https://prnt.sc/R7xwTlIFY-9m
2. Under the Response viewer: Go to Survey >> Analytics >> Click on the drop-down to select Completed: https://prnt.sc/F8uvVXbhCFBo
3. You can also get the count of Completed responses on the survey index page: https://prnt.sc/mMWCbnAzvJ5P