Most arranger players are merely hobbyists, beginners, or just do it for fun. Few people's playing skills, whether they call themselves pro's or not, is stellar and that's reality.
It is probably not difficult for an hobbyist having a $20,000 arranger and other expensive recording gears to make a good demo of the arranger's styles like this one made by Frankieve
https://www.youtube.com/watch?v=v_cw98ardXI If youare talking about $20.000 instruments from wersi..
They are not arrangers but Organs. There is a huge difference in price between a simple Arranger and a majestic organ..
The Wersi TOTL arranger is much cheeper then a tyros, an Audya or a pa3x, tough admittedly, its not an open arranger, but still a TOTL arranger.