The S20 Ultra exhibits a noticeably warmer colour tone, but I think it ultimately comes down to a matter of personal preference. The camera does a good job of resolving finer details in a complex scene like this one however, and you're better able to make out things like the edges of the leaves in the crowded foreground.
The S20 Ultra leaves no doubt that its a Samsung phone in the picture below, gleefully dialing up the reds and greens in the image. There's even some natural depth of field to be had here, and there's an obvious softness to the background foliage around the flowers.
The S20 Ultra has the most vivid colours in this shot, and it manages to preserve detail on the boardwalk that the Pixel 4 XL doesn't retain. However, it still continues to smooth out detail in the shadows, as seen in the shaded trees here.