Since remastered versions of DS9 and VOY aren’t happening any time soon, I think the next best thing should be a SD-BD release, kinda like how Discotek Media are doing with some old anime titles...
TL;DR TNG was filmed with actual film and converted to tape for vfx and broadcasting in SD. The conversation to blu-ray cost $10 million dollars as they had to redue all the special effects. Both DS9 and VOY were filmed the same way and no one at Paramount is interested in creating a physical remaster on blu-ray for limited sales it seems.
How to get DS9 and VOY on Blu-ray
Since remastered versions of DS9 and VOY aren’t happening any time soon, I think the next best thing should be a SD-BD release, kinda like how Discotek Media are doing with some old anime titles...