That’s not a Workflowy API then.It should be possible to streamline the process by sending the draft content to a Shortcut which then shares directly to Workflowy.
However, having installed Workflowy and created an account, every time I try to share to it from any app I get prompted to login and then when I select to login I get jumped into the app and nothing is shared. So I’m just stuck in a loop where I can’t share anything to Workflowy.
If you have sharing working on your device, then I would suggest building a shortcut using the “Share with Apps” action step and the Shortcut input as what is to be shared. Then in Drafts, create an action with a single step to call that shortcut, passing it the draft content.
Unfortunately, it also doesn’t look like the URL scheme situation has changed since this discussion.