All depends on the the individual.
For example, when I first purchased the QU16 in 2014, I set up the mixer in the house and spent a week getting to know my way around it before I took it out on the road. With the CQ-20B, I purchased it on the Monday, had a band rehearsal on the Tuesday and used that time to set it up before using it for its maiden voyage on the Saturday and Sunday. With using a digital mixer, especially an A&H over many years, you get to know the layouts pretty well aiding in being able to jump straight in without too much trouble.
Even now I still find the stock app awkward to navigate around compared to the QU and SQ app.