Sorry for the late reply. But - a good place to ask those questions related to DQL would be on the Dynatrace community -> https://community.dynatrace.com

I think for this use case we have the command KVP (Key Value Pairs) that automatically parses Key Value Pairs and you can then access all keys and values. Here for instance a discussion on that topic => https://community.dynatrace.com/t5/DQL/Log-processing-rule-for-each-item-in-json-array-split-on-quot/m-p/220181