Highest quality versions would be the SD broadcast rips, I believe?
Harmy made a reconstruction of the 1997 Special Edition version of A New Hope, and Team Negative 1 made a 4K upscale of a theater used 35mm Special Edition print of A New Hope, too.
Link to Harmy’s reconstruction of the 1997 Special Edition version of A New Hope:
https://originaltrilogy.com/topic/Harmys-STAR-WARS-Respecialized-Edition-97-AVCHD-and-MKV-Released/id/16682/page/1