It is more of a combination. Everything in life needs practice but in a sense you are going at it the wrong way.
What do I mean by that?
First of all what is your goal? Do you just want to get better at drawing or do you want to make a comic?
The goals may be extremely related but they are completely different at the same time. Depending on your goal is how you need to tackle the problem.
If you only want to get better at drawing there are multiple excercises that will help you get to your goal way faster.
For starters:
1.- drawing backgrounds.
2.- improvising the same image multiple times under a specific time. Let's say 5 minutes. Repeating the excercise 3 times.
3.- drawing the same image under 1 hour, then doing it again but with 2 hours, then with 4 hours, then 8, then 12, and finally 24 hours. The more time you have the more details your painting should have.
4.- using different styles to draw. Basically getting out of your comfort zone.
5.- drawing nudes (classic art excercise).
6.- drawing feet (many people avoid it and when they do draw feet they usually add socks to avoid drawing all the details feet have).
Note: Being good at drawing does not mean you will be good at making comics since you have to think of the story plus adapt your drawing style to how comics are made. Plus you have to be good at selecting fonts among other things.
If your goal is to draw a comic, you have to keep a style always.
You will improve at drawing your particular comic style. This will not give you lots of practice to improve your drawing skills in general. You will basically stay in your comfort zone.
If your goal is to only make 1 comic with 1 particular drawing style then that is perfect. But even then consider you still have to practice around 1000 hours any skill before you become decent at it. If you want to be an expert you have to practice 10,000 hours.
2 hours a day is not enough drawing practice if you just started. 3 is more decent. Having said that YOU CAN'T PRACTICE DAILY or more like you shouldn't. You need a break. No natter what it is you are practicing if you do it daily and without breaks your body or your mind will eventually fail. Many people who draw daily get problems with their wrists.
What I'm trying to say is... that you need to put a good amount of hours to practice with breaks every 45 minutes or so (each break like 5 minutes long) and limiting the days so your wrists and mind can truly rest and recover from all the stress they get.
A rookie mistake is trying to do a lot more than what your body is capable of.
Your body is a delicate and wonderful machine and you should treat it as such.