There is a guy on Reddit who has tried upconverting some episodes from the DVD versions trough AI machine learning. He posted some clips on YouTube. Keep in mind that YouTube compresses these heavily: Intro: Battle form "Sarcifice of Angles": He also tried it on Voyager. You can read about it here. There is also a link to a longer sequence that one can download in uncompressed 3840x2160 resolution and watch on a 4K TV. Eventhough it's obviously not anywhere near the TNG-Remaster, it still looks pretty good.