On the topic of draftsmanship, if you feel it’s your achille’s heel then perhaps you would make more gains in the 2D category. Time spent is directly proportional to quality achieved. If you spend 60 hours on one sheet of paper/canvas/pixel spread, your result will look fantastic and your skills will be amply rewarded. 60 hours is only one hour a day for two months, after all.
Or you could try dedicating the first month towards your concept “sketch” and your second month towards everything else. Your chances of finishing may decrease, but so what?
As you may have guessed I’m a big proponent of traditional drawing skills. I think they’re worth the hard work & frustration involved in the learning process.