It was not formatted as pre-formatted text so it failed when I tried to format it but I just edited your post to format is properly and now you can paste that same text into https://codebeautify.org/jsonviewer to see the data structure:
When I click on the CZT key, it shows the path to that value at the top (object → 1 → CZT). So in Thunkable, you would set the property “[1].CZT” or set the property “CZT” of the first list item in the object.
I haven’t set JSON properties before so if it were me, I’d make sure I can get that key value (“CZT”) before attempting to set it to something else.
You can find out more by watching my tutorial video here: API JSON Tutorial (Video).