Hi Jamon, fehmi2029,
Welcome to Affinity Forums :)
The Apple (Core Image RAW) engine is only available for Mac since it's provided by Apple in their OS.
Hi Shaw,
Welcome to Affinity Forums :)
I've downloaded a few sample NEF files (Nikon D5200) and tried them both on Photo for Mac and Windows but i'm not seeing the same issues you are experiencing.
Can you please upload one or two of your RAW's so we can check out what's going on? You can so do using this link. Don't forget to add your forum's username to the zipped file name.
Thanks.
fehmi2029 reacted to MEB in RAW images open different than original - Photo