The way I'd say to do it is to jump, then dash, then mash the jump button. I will say, the timing is pretty lenient after the initial jump; you just have to mash the jump button, not necessarily time it perfectly. The one NPC in particular who tells you how to do it is in the Wall Jump room. It shouldn't be any harder now than it was in previous updates, you just can't do it in 1x1 gaps anymore. I'll check the tutorial room though; I think I have an idea of what's causing that.