Thumb picks are great, but they are really hard to get used to. I avoided them for years because they just didn't feel right. Then I actually sat down and gave them a chance. I forced myself to play with them for several months. Now I play with them regularly. I use a Dunlop 9003P large pick. It's the only thing that will fit my fat thumbs.
2-3 hours per day! That's impressive. I used to practice until my hands hurt. Now, I barely have enough time to play 15 minutes each day. I think it's more about consistency than it is about actual time. Keep constantly learning and improving, and you will be a better player.
Sounds like I need to take my own advise. lol