I can't get beyond this...
My initial plan was to trade part-time after work and slowly build my account, but it turned out to be much harder to do than I anticipated
Why do you think that you can earn, say, $1K/wk to live on when you weren't able to earn a few bucks/wk part-time to grow the account?
Coupled with this...
One thing which will be different than earlier is that I will try to focus on consistency of returns instead of trying to hit home-runs every single day.
And now you have a DIFFERENT, un-tested/un-tried game plan. Which likely has a different set of execution requirements and machinations. Seems to me you have put the horse before the cart... consistency should be a goal whether you are growing the account, living out of the account, or both! This new un-tested, un-tried game plan is where you begin and refine. You're doing it backwards IMO.
As someone mentioned, spending more time in front of the quotes DOES NOT (by default) equate to more profits. It may however, by default, equate to more trades, which may also be different for you.
All that, to make a living, you need a business mindset to help determine your success or failure. You are starting with a 15K account. You need to pay yourself... Starting out I'd use 1K/wk as a wage, since that is near the "average" wage in the USA. Therefore, this means 4K as cushion. IOW, you only have 11K to trade with.
Whatever wage you decide, whatever pay period you decide, weekly/biweekly/monthly,
YOU WITHDRAW the appropriate amount. With 11K and a 4K cushion, you will have a 1 month cushion with a 1K/wk wage... The cushion is replenished via profits. If you've replenished more than your expenses that means you are growing the account. Else you are losing or breakeven at best. If growing, you can adjust your trading capital. If losing you have to adjust your trading capital, your expenses, refund the loss back to the account, or quit! Either way, you have to pay yourself via withdraw. There is no Dunning-Kruger effect when done with an actual business mindset.
Can it be done? AB-SO-LUTELY!!
Your post however, poses significant challenges, IMO.