Thanks for your patience. You will find my answer underneath the respective questions
1.whats the miminum configs needed to set cache for post request based on the body content (while having other endpoints too).?
You need to set the path, method and response code
2.is cache_key_regex is part of the url of the request or part of the body?.
It’s part of the body.
3.is it okay to leave cache_key_regex=null and path=null. so it will cache all post requests
of the basic graphql url or are there other configs needed so it will not effect the other endpoits?
Yes I think so. I have been testing this out to know the result and it looks that way. You could also use a regex in the path to affect only very specific urls.