@Rakesh Govindaraju I have seen and built a few ways of doing this.
C360
You can build various fields on the C360 for the CSM to manually update. This will allow CSMs to manually update the data and you can use a CTA to notify them to fill it in or if its not filled in.
C360 Related List
The other option I’ve seen work well is using a related object and adding it to the C360. For this, you would need to create a Low Volume object so that the CSM can add a record and or update an existing one. This works well if you want to keep a historic record the different versions of the data. Do make sure you add the GSID to the report to get the view/edit actions to show up. More on this in my idea here: https://community.gainsight.com/cs-ideas-21/simpler-ability-to-view-low-volume-object-on-the-c360-38559
Survey
The other option that I have seen work is to send a survey to the CSM to ask them all the questions and fill in the data. This data can then be added to the C360 via Related List that’s filtered for these specific surveys. Alternatively, you can load this data to the C360 fields using a rule.
This option requires a bit more heavy lifting but it will be a better interface for the CSM to enter the data. It is a bit cumbersome though because you will need to make sure CSMs have correct permissions to both edit a survey and view it.