Though I've been playing since the early 80's, before I started that final (and successful) time, I had a few prior attempts though with less than ideal guitars. Two things happened when it finally stuck: (1) I had a guitar that wanted me to play it (my first guitar was a Les Paul), and (2) I felt the need to just play. When it 'stuck', it didn't matter if something was difficult or not, I just wanted to play. Even when stuff seemed more challenging, I just didn't care. I enjoyed it whether easy or hard.

Some of that is mindset; not thinking of guitar as 'work' but as something that is to be enjoyed. Even when you're working on hard stuff and not getting that 'thing' you're working on out of the box.

One of the first songs I learned on guitar was Led Zepperlin's 'Black Dog'. It's never been an easy song to play. Truthfully, I didn't think of it as a tough song in as much as it was something I wanted to play so I just stuck to it until I started making it work. Sure, once in a while, I might have used an adult word or two getting the pattern down but never did I think what I was doing was actually work. Even when I was working at it, and not getting it, I still wanted to play.

This kinda sounds like where you're at. If you embrace the fact that you will always be learning on the guitar, it becomes that things that will always keep you engaged. Some stuff will be easy and others...not so much.

Good Luck!!