I got a response from another query I had (see here). In the response it was mentioned PiMax are currently mass-producing all the Crystal Super line (headsets and optical engines) at the moment and batches are shipping each week. They are expecting to fulfill all open orders for standalone optical engines between April and May 2026.
Take the above with a grain of salt, but perhaps a pinch of optimism might not hurt either?
So, keep your eyes peeled - and good luck! 