Also Scott, if you want to spice up the songs from earlier grades, there is a website called Moises.ai which allow you to make a backing track out of your favorite songs.
It removes the guitar from the original recording track and you can record your own playing into the track with a DAW or just play along with it.
For instance, if you check my rock songbook project , I mostly played the rhythm guitar (chords), but in the context of the backing track, it’s pretty easy to recognize the songs if you know them. And I learned a lot about the rhythm while doing it. And I had a lot of fun even if I was not playing “all the parts” like the singing and the solos.
The rock songbook is a little bit more advanced than the beginner songbook, but the same could be done with it or any song lesson from Justin.