two things i have to say :
one, no matter how good or bad you are, you’ll have good and bad days that feel unlosable or unwinnable. you (hopefully) end up realizing that it’s better to just write those off as lucky (or unlucky) and extract whatever fun or value you can out of them.
two, i want to try and offer you a different way of thinking about how we actually improve at things as humans
imagine you’re starting again, from zero. you just picked up the game. what do you do? do you: a) learn everything ahead of time, or b) guess and make things up as you go along?
the answer is, obviously, b. even if you try to learn ahead of time, everybody is going to be assuming certain aspects of how to play. you still are, we all still are. that’s what makes us unique as players, gives us playstyles, gives us strengths or weaknesses etc. it’s like that in every game, and not just in games, we do it when learning pretty much anything. it’s all, mostly, improv. even in a game as old as chess, humans still haven’t “solved” it to the degree computers have, so we definitely haven’t in overwatch.
there are two things working against you:
- overwatch is a very chaotic game, where the same action does not always yield the same result, because there are so many variables. choosing to flank at a given time will work against one team, but not the next. it makes it very difficult to improve on your own, through trial and error. some people do, but it’s usually always faster to cut the trial and skip to the known solution (this is what coaching and vod reviewing does)
- many of these guesses that we make turn into long term habits, whether we realize them or not, and a lot of the things we do tend to build ontop of those old habits. it can be self destructive if you’ve made the wrong guesses; for exmaple, how to time engages, how to use ults, where to position and why. (this is also another reason vod reviewing and coaching ranks people up so fast - it forces you to acknowledge these habits and improve them)
simply playing for a long time doesn’t guarantee you’re going to improve, it’s only going to guarantee that you’re more experienced than somebody new. but how useful is experience, really? if a total noob guesses how to time their engagements better than you and has better mechanics, both can be carryover skills from other games, they’ll smoke you. it doesn’t matter how long you played 
you don’t need coaching or vod reviews to overcome those problems, but if you’ve been stuck for a long time, it might help you get “unstuck” if you seek out answers to specific problems
