One manufacturing technique that is often neglected and I’m not sure if rightly so, is thermoforming.
It can be done manually as well as highly automized and is dirt cheap. Very good for a certain kind of 3D shapes without undercuts. ( But can do undercuts as well, if needed). Best for flat shapes and hemispheres. Can be welded. Like carbon fibre it needs post processing - cutting off the edges.
I’ve got modelling, 3d printing and a bit of thermoforming capabilities, so if you’d like to explore that I can help you.