Samsung calls its Portrait mode Live Focus, and it comes with more options than you get on other phones. Instead of just blurring the background, you get different effects like Colour point, Zoom, Spin, and Big circle. I'm still more interested in the simulated bokeh effect though, which you can also adjust after the photo has been taken.
The S20 Ultra has a DepthVision Time of Flight camera that can judge depth and distance, and this is supposed to help better differentiate between the foreground and background.
There's is good improvement compared to the S10+, and the S20 Ultra is able to come up with a far more pleasing bokeh effect. It also produced more flattering skin tones, and the resulting picture is warmer than the Pixel 4 XL, which has a considerably cooler cast (although some of that may be due to the sun's rays peeking out at that particular moment).