If you haven't had the chance to read one of Bunnie's hardware teardowns, you're missing out. His teardown of the Form 2 3D printer (https://www.bunniestudios.com/blog/?p=4641) is a great example of his work.
That's a nice description of the Form 2 3D printer. You don't see that grade of engineering from most startups. That Formlabs makes their own mirror galvanometers is impressive, but probably necessary. The off the shelf units are either low-precision ones for light shows, or small-volume scientific instrument components.