Welcome to the community @bjoliveau !
I’m curious why you are using the execute command node instead of using the HTTP request node instead? There is some adjusting to the different interface but I find it works well. Here is a post where I convert a cURL request to HTTP request.
However, it is possible to accomplish what you are trying to do with the execute command node. This workflow shows what you need to do, but the specific function you will want to add after the execute command to parse the json is below: