@WXM:
Thanks for the notice that downloading is better than watching as stream - it’s something I always do but forgot to mention, my bad.

As far as the NTSC-DVDs go: It’s a bit of a complicated process, but generally I have found that the NTSC have better quality in the CGI/VFX area, since they haven’t been adjusted for PAL distribution (25 FPS).
With my workflow, I reduce the 25 FPS PAL to 23,976, which looks nice for about 95% of the live action segments, but it really hurts the effects, which are already stuttering (coming from 29,97 FPS half fields). Since live action is mostly shot on 24 fps film stock, the 23,976 fps from PAL are ok.

My modifications now include:
Taking the NTSC and restoring to full fields (which creates 59,94 FPS output), the render them to reduce rainbowing and increase detail, then I eliminate frame doubles and blend the rest together so I get 29,97 FPS again, then I use an AI-based solution to reduce further to 23,976 FPS (without actually changing the number of frames/images in the videostream), then I do 3 upscaling runs with different models and finally I compare the number of images from the PAL stream to the NTSC stream. Usually, there is only a difference of 1 image, but to avoid losing audio sync I delete 1 image that isn’t as “noticeable” which works quite well if you can simply kill a black image during fade-in/fade-out.

The only thing left I want to do is to add FlowFrames in my final workstep to further smooth out the effects - then perhaps it could look even better.