@George, welcome to Keyboard Maestro (KM) and its Forum.
KM is one of the best Mac automation tools available, its Forum is one of the best and friendliest forums on the Internet. Whenever you reach a tough stumbling block trying to use KM, please feel free to post your question/problem here for help.
Now, to your question/request:
I have no doubt KM to easily do this automation for you, as we have done it many times for similar requests.
But, to start with, you need to provides us with more information.
We need real-world examples of:
Your source data
Be sure to provide enough examples to cover all of the cases (variations) the data might come in.
Do NOT "clean up" the data. Give it to us exactly like you will be receiving it for processing.
The results you want
Please put both in Forum Code Blocks, using "text" as the language.
Also upload a zip file of the spreadsheet (Excel?) file both BEFORE and AFTER the data is processed.
Then you can process the text to find the desired strings. As @JMichaelTX mentions, its not entirely clear. What do you want to find? All the cases of "asin":"DIGITS"? In that case you can use the For Each action together with the Substrings In collection, using a regular expression like: