I've been using CodingamerRemoteService/loginSiteV2 but recently the API changed, now taking 5 params, the last is using reCAPTCHA so I don't think it's realistic to automate in python. But maybe you could copy the session cookie from the browser into your code?

Sorry for the late response, I didn't get a notification about your comment.
I've found a way around it, using the cookie of an existing session.

Very nice and interesting playground!