Go for Go. Industries are adapting it like crazy! Plus good Go developers are scarce so as a freelancer, you will have increased opportunities. Also, to a fellow freelancer, I would like to suggest you making plugins for chrome and Wordpress. No matter how crowded their store looks like, there is still plenty of room of requirements. Here's my website https://boosters.in created on wordpress! I personally had to create a wordpress plugin for such a small website and small usecase. So I'm sure the world is full of possibilities. Have a good day!