Electric guitar...
I started teaching my son on an acoustic, playing bluegrass. A lot of bluegrass lead work is directly related to rock lead guitar work, so once he learned the patterns, it was all about picking up the speed. One trick I taught him was to play in the dark, or with your eyes closed. Play very slow and methodical, making sure you play each note correctly. Then go around the pattern again a little faster each time until you start messing up, the fastest you can play without mistakes is the tempo you start at next time you practice.
here’s a guitar I bought about a year ago, just on a whim. It’s a 72 SG, one of the most effortless instruments to play that I’ve ever owned. I paid $1k for it, it’s worth about $3k.