REST API help using the Jetpack plugin

I’m attempting to setup a Powershell script that will create new posts on my self-hosted WordPress blog. I’m attempting to use the WordPress API by having the Jetpack plugin installed.

I’ve managed to read my posts but when I need to do anything that requires authentication I’m struggling. I’ve followed the developer documentation https://developer.wordpress.com/docs/oauth2/ and can get my script all the way to the point where I need to get the code in the “https://developer.wordpress.com/?code=cw9hk1xG9k” URL that I should be getting redirected to.

I’m getting hung up on this statement “Once the user has authorized the request…”. This is my blog and it only has 1 user. Is there a way I can get around having to explicitly authorize a user? The process works if I manually bring up a browser and authorize the connection but that defeats the point.