you can also get the nested subscriptions
https://developer.khoros.com/khoroscommunitydevdocs/docs/retrieve-nested-subscriptions-for-a-node
You can make this call if you logged as an Admin
https://yourcommunity/api/2.0/search?q=SELECT%20*%20FROM%20subscriptions&restapi.response_style=view&restapi.response_format=json
However,
you can not run this call via Postman, I've tried any possible way and created a Khoros support case and reached to their devs for that, Waiting on the response.
https://{{hostname}}/api/2.0/search?q=SELECT%20*%20FROM%20subscriptions LIMIT 1000&restapi.session_key={{sessionkey}}
I can make many of the api calls except of the above...