> I'd just start with learning all the notes on the fretboard, [...] and scale shapes

This is not as simple as it sounds. It seems, from my experience of learning a guitar and observing others, that there is something inherently illogical how tonality changes between strings. There are two main ways to do it, either you remember by memory, or you simply hear what happens. Both are hard for average beginner, because it just doesn't make sense.

After I have been practicing a guitar for quite some time I started learning a piano for some reason, and seeing the keys in front of me it all made sense instantly