REST Option-List dependent on Existing workflow Input

Scenario:
There’s an existing workflow with a simple key-value input from a manual option-list.
There’s a need to inject user output from that option into a REST option list as a variable.

What will be a good way to make this work?

Additional note: REST Option-List generally states the request isn’t formed correctly with error 400. I am unsure if the variable I am calling is null from the manual option list or if there are issues with the way I’m formatting the request script.

Are you attempting to use the output from Option List 1 in the URL of Option List 2? Or are you utilizing the request/translation scripts?

Attempting to push output data from Option List 1 into the REST Option List 2 via a request script