let jsonData = pm.response.json(); pm.environment.set("test_name", jsonData.test3[0].id3); test3 is an array so you have to get the first object and then id3

Never try to unify something without having a unified thing. Refactoring or optimization is done only if there is working code to compare the results. In your case, write a few examples by hand and then try to find a common denominator. The transition should always be from simple to complex.