I recall watching a movie that was converted from black-and-white to color as a child. There were many distracting artifacts. Most notable was the hairlines of the actors would shift as the actor rotated their head. It made the film unwatchable.
I'd be curious to see an ensemble-based super-resolution, where each model can output the confidence of a pixel region, then have another network learn to blend the result.
Conversely, these results are achieved using a single top-of-range GPU. Everything fits in memory for a batch-size 15 at 192x192. By distributing the training somehow, you could make the network 10x bigger and train for a whole week and likely get much better general purpose results.
I have a side business doing Film restoration and am not aware of any solution like that. Probably the best upscale solution there is is from Teranex, acquired by BlackMagic Design. Evertz probably also has something in their offering.
In theory you could use this to increase temporal resolution as well. Turn 24 fps movies into 60 fps, and upscale regular HD to 4k.