AFAIK wheels are heavier this year which means more unsprung mass so it’s going to be difficult to balance softer setup for riding kerbs and stiff enough for high speed, not to mention RB20 has high Cg (central cooling, heavier liquid cooling) compared to RB19 which again requires stiffer setup.
I’m delighted that they fixed low speed but is it at the cost of high speed or medium speed? Time will tell.