DF will probably come out within the next 2 weeks, and most likely before S5 ends. Just watch out as DPS is a popular class to main, and if you get stuck with many other DPS mains it can hurt your team's capabilities.
That's why I'm a flex despite my interest in DPS and Defense heros. There's times where I need to go Ana over Pharah, who is my main, or where I have to go Winston (before dive was meta and people claimed he needed buffs) because we needed a second tank to dive a Widow over me playing what I want to.
One of the best skillsets in the game is to main at least 1 hero in each category so you aren't helpless if you can't play your primary class. Since I'm a flex, I play a lot of everything and just today I got a 5 man potg as Zarya, which I would recommend as she can utilize Junk's skillset.
Oh I have no doubt about this. It's just that this game will start requiring you to not solely focus on you individual skillsets, but start focusing on your team skillsets, like grouping up, target prioritization, and ult recognition/comboing.
The best example I have for this would be how I carried my way up and out of Gold and Plat into Diamond, however reaching masters is extremely hard for me because I don't utilize team ult coordination, as I am an opportunist since Pharah is easily killed when she ults, I have to ult when I have the best window.
I also don't think I've added you yet, so mine is Xplo#11534 in case you get your SR up to at least 2000 or if I drop down to 2500 (unlikely as I rarely play alone now) or if you wanna do some QP. A good way to get my attention outside of these forums and PMs would be to use my discord: https://discord.gg/bW2xUKw (open for anyone).