@Edward_Brown, so is the idea here to store the Hubitat variables and their values in the stringified JSON dictionary format in a device’s attribute, and you want the PARSE feature in Rule Engine to parse the JSON string and access the specific variable’s value by using the variable’s name as the key?
In case you are not aware of this, you can pass Hubitat variable value to SharpTools by following the steps in this post. It needs a RM rule to call SharpTools HTTP trigger and pass in the variable when the HE variable gets updated, and the SharpTools rule gets the value and assign it into a SharpTools variable that can be used in both dashboards and another rule afterwards.