As for practical guns I have wanted a PX4 Storm to send to Landon Tactical. I never got one because, well, they are uglier than a lever action rifle with rails. But by all accounts they are the flattest shooting common 9mm.
Anything full size and 9mm is pretty dang soft and flat.
Heavier is better, so something like a Shadow 2 is absolutely softer than a G17.
Comps/ports can make it even flatter.
But the reason guns don't shoot flat for most people has very little to do with the gun and everything to do with their grip.
A shooter with good grip fundamentals can make a stock glock 17 shoot "flatter" than a bad shooter with a tricked out comp'd gun like the ones in OPs video
Kimber Rapide 1911 5" and Springfield Prodigy 5" are probably the flattest I own. Rapide has a brake on it which helps and the Prodigy has enough weight to keep it down.