The Astro update #43 (10/27/21) provided these "guesstimates"
16th November - All materials arrive for PCB mass production - many have already arrived
End of November - Astro PCB mass production
30th November - All materials to arrive for Astro Assembly
1st half of December - Astro Assembly and packaging
Mid-December - 1st Shipment of Astro Slide from factory to Planet warehouse
Fitting the events above, as best as I could, to makoshark's milestones, gave me these earliest possible dates:
(PCB) Production Start: Cosmo-09/03/19 >> Astro-10/28/21 >> #43-11/16/21
GMS Approval: Cosmo-09/06/19 >> Astro-10/31/21 >> #43-ongoing as of 11/05/21
Ready for Assembly: Cosmo-09/18/19 >> Astro-11/12/21 >> #43-11/30/21
First Mass Production: Cosmo-09/26/19 >> Astro-11/20/21 >> #43-12/01/21
Start to Ship: Cosmo-10/12/19 >> Astro-12/06/21 >> #43-12/16/21
By "earliest possible" I mean that the "End of November" Astro PCB mass production cannot possibly begin earlier than 11/16/21, when the required materials are expected to have arrived, and will likely not begin until a few days later. Likewise, the factory cannot possibly be ready for assembly earlier than 11/30/21, when the materials for that are expected to have arrived, and will likely need a few more days to set everything up. Further, shipments from their warehouse cannot possibly begin earlier than "mid December", when the first shipment to the warehouse is expected, and will, based on the Gemini and Cosmo, not begin until a week or two later. December 16 isn't specifically mentioned by Planet anywhere, I just picked that as the middle of December.
One date to keep in mind might be Saturday 01/29/22, which, as far as I know, is the last working day before the, certainly well deserved, Chinese New Year holidays. New Year's Eve is on Monday 01/31/22 and on Tuesday 02/01/21, the year of the Water Tiger begins. What hasn't left China by 01/29, isn't likely to go anywhere until after the Lantern Festival on Tuesday 02/15/22.