There are two reasons for this, first, while sharing the survey you need to permit the person with whom you are sharing the survey, in this case, if you permit to review then the other person will get the comment page only. In this case please go to the share survey and update the permission access to Edit.
Screenshot: https://prnt.sc/qRAxCVbUgvwP
The second reason is survey status being collaborate. Before or after sharing the survey, if you change the status of the survey to collaborate then if at all you share the survey with edit access, you still be able to see the comment page. In this case, please go to the main dashboard and change the status of the survey to active (https://prnt.sc/BX0qCR-MzDAg) and your colleague will be able to access the survey and edit the same.