Convert JSON value in single row in TSQL 2019

I need help in transforming a string to json to put the values in separated lines. Using tsql (2019)

How do I have to transform the provided data (payload) into a json to create the expected result or is there another way to splitt the data?

Thank you in advanced.

AS for the main keys it works but I would like to have the interests in separated lines as well current result:

Expected Result:

It seems you just want a dynamic OPENJSON call.

SELECT
  t.CustomerID,
  t.[key],
  j.value
FROM YourTable t
CROSS APPLY OPENJSON(t.payload_json, '$.' + t.[key]) j;

db<>fiddle

What the relevance of the payload and value columns are to the question I don't know, your logic is not clear.