Hi babyhum, I Wouldn’t say I’m any sort of expert but would’nt mind helping if I can.
I’ve been using ffmpeg which isn’t really a true upscale but rather a resizing and clean up, I’ve used it on Adywan’s TESB:R SD dvd he did and his ANH:R SD and also Harmy’s Re-Specialized and the results have been really good.
I also got REAL-video-henacher which is a free tool that is really good but requires a lot of time, If there’s anything I can do to help please just ask 😄

The scripts I use for ffmpeg are

Professional SD-1080:

ffmpeg -i input.mp4 -vf “yadif=1,hqdn3d=1.5:1.5:6:6,deblock=filter=strong:alpha=1:beta=1,scale=1920:1080:flags=lanczos,unsharp=5:5:0.8:3:3:0.4” -c:v libx264 -preset slow -crf 17 -c:a copy output_1080p.mp4

Super Sampling Upscale ( this one upscales and cleans the video to 4k and then downscales to 1080 for a clean look ):

ffmpeg -i input.mp4 -vf "
yadif=1,
hqdn3d=1.5:1.5:6:6,
deblock=filter=strong:alpha=1:beta=1,
scale=3840:2160:flags=lanczos,
unsharp=7:7:1.0:3:3:0.5,
scale=1920:1080:flags=lanczos
" -c:v libx264 -crf 17 -preset slow -c:a copy output_1080p_super.mp4

Obviously with these ffmpeg scripts the orginal video quality is a big factor in the output but honestly if there is anything I can do to help please let me know 😃