Short questions

Q6
Do you expect to use M.2 devices as data store?

[Rob for Cosmos]:
There is no reason (that I can think of) preventing M.2 devices being used as cache or capacity for the Storage Spaces Direct pool.
We don’t really care about the physical form factor, as long as it speaks NVMe.
However, a consideration would be serviceability – it’s internal and therefore hard to access, and it’s generally not safe to replace without powering down the server.
AFAIK, the main appeal of M.2 is the small size, e.g. for laptops. For servers, I don’t see a clear benefit - but it should work.