What model or method seems to work best for DVD 720x480 to 4K 3840x2160 results

I been trying to find a good match here on my days off to convert and upscale a DVD series I own (Real Footage not Animation) that was shot in high / medium quality without interlacing to 4K for my media box to watch on my new 4K TV. So far I found some good results doing a direct upscale from the DVD footage to 4K using a few models which have increased details nicely. However some parts come out very weird. For example, scenes that involve trees, grass or other foliage come out looking like polygons or other artifact shapes of green combined together to make structures. It’s a very weird and unnatural effect.

I found this to happen with Proteus (Artifact shapes of the same design combined together), Iris (But with blurring added to the effect), and Gaia (Very detailed but very computer like then natural)