Hey Tom,
ok, you can only use RAWs (any kind) in RC if they are supported/recognized by windows, as you already said/quoted.
This is the case when you can see thumbnails and use the windows viewer to display them.
From what you said so far I gather that this is not the case for your PC.
Now you can either contact Sony or Microsoft about this, but from what I have read they just blame each other respectively to be responsible for implementing it. Did you look if Sony provides something?
I found this with two clicks: https://esupport.sony.com/swu/4022/US/
If not, your only option left is the software that I have pointed out (referred to by Wishgranter), although I have no experience with it myself. It does the same thing, it is basically a third party codec with some more functionality (e.g. faster thumbnail display, I think). I’m not advertizing, just trying to point out a possible solution.
Or just develop them into Tif or Jpg…