Did you look at the Balkan ecology project?
www.balkep.org
Their courses always seem good value and I'm very impressed by their professionalism and ongoing commitment to recording and demonstrating their activities.
I know they're running a september course, but I don't know where they stand with interns and such. Maybe drop them a line?
Also John D Lui is trying to start his ecosystem restoration camps
https://www.ecosystemrestorationcamps.org/
I'm impressed with what he's trying to do, and if it works then there's a good place for many people to network and learn stuff.
My choice would be Richard Perkins in sweeden.
http://www.ridgedalepermaculture.com/
I know he takes interns, but you're almost probably too late for this year. If I'd have had the time and could have afforded the time off i'd have done his farm planning course. It wasn't cheap, these are professional fees, but from what I learn from his youtube channel,
I know it would be money very well spent.
That's all I have for you. I hope youyou find something useful!