DSD512 native? Such as from?
Not on NativeDSD though. In case you weren’t aware; https://www.nativedsd.com/dsd-512/
NativeDSD is the only store to sell DSD 1024 and DSD 512 music. These rates are mastered by Grammy® Award winner Tom Caulfield through HQ Player Pro.
Personally, I’d stay clear of those! 
As for the other points in your post, I think both the question of the Upsampler’s future, and of DSD256’s support on dCS platforms have been addressed widely before, not sure there’s more to rehash?