Most of the materials you mentioned have lots of problems with residual stresses. Even if you machine them to given tolerances, they will again be out of spec in a year or earlier. This problem also important for high precision CNC machines (and the typical precision of such machine is measured in micrometers, not nanometers). This is why the machine tables are mostly made from cast iron (not steel) or granite - both can have very low residual stress, but granite is way better - it’s also used in best computer controlled measurement machines.
Residual stress is especially problematic in chemically cured materials like concrete or epoxy and polyester resins - these materials typically shrink during curing. If used as a part of composite material like steel reinforced concrete or carbon fiber reinforced plastic, residual stresses result form reinforcing material not shrinking with matrix. At work I set up measurement equipment for experiments with various composites, and from what I’ve seen, I wouldn’t expect much dimensional stability from them.
As @jerwin said, beryllium mirror would also be a good choice, but I suspect that cooling times would be similar to glass, and machining costs would be far greater - beryllium is extremely toxic, especially when ground into fine particles.
Edit: The processing time of 36 months is also not that much compared to largest lathes and mills. For such machines, casting and machining main parts can easily take 10 years.
