On Mac and Linux the option to open the USD Stage window is not there like it is on Windows. This is not a regression since USD Stage was not preset in 4.23.1 (CL-9631420) on any platform.
Results: There isn't a USD Stage option under Window
Expected: USD Stage would be present
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-85966 in the post.