u/HowDeepDoYouBelieve

If there's something that could help me focus for 6 hours straight that would be awesome, but if not that, even maybe like 2 hour focus sessions followed by 30 minute breaks, up until I practice for 6 hours a day.

Is there anything that could help with this? I may be deficient in sleep as well, I try to make up for it with naps.

Also I wouldn't want anything that makes me jittery or makes my muscles tense as that could potentially negatively effect my playing.

I'm looking to take online lessons. I currently am working through AbsolutelyUnderstandGuitar, FretboardBiology, and PickUpMusic, but I feel like I am not doing enough/could be making mistakes, and none of these things teach me ear training.

I genuinely want to become as great of a guitarist as I can. I have a goal of being a professional musician someday. I don't think I can afford actually going to school for it, but I can do online lessons, and practice for 4 hours every day.

Can anyone give me some suggestions? Specifically looking for an online instructor that specializes in ear training for guitarists.