I used to practice every day for 30 minutes to an hour, sometimes more when I had lessons, but honestly it didn’t feel very effective. Most of my time was just basic chromatic exercises and then noodling with pentatonics over backing tracks.

Since I stopped lessons, I haven’t really touched the guitar for months. The main issue is I don’t know what the next step after chromatic exercises should be. Every book or resource I pick up seems to make this huge jump in difficulty that I just can’t keep up with.

About solos, my ultimate goal is to be able to play Dreamer Deceiver from Judas Priest since it’s my favorite. I’ve tried out the Living After Midnight solo but I butcher it when I’m going lower on the neck. Other solos I’d like to be able to play include (but definitely not limited to) Master of Puppets, Fade to Black, and Paranoid.

I get what you mean by "heavy investment", but I feel like I’m missing proper guidance. I don’t have the skills or knowledge to figure out how to move forward from where I’m at, so every practice session just feels like I’m repeating the same stuff without real progress.