I try to take an objective viewpoint on this matter wherever I can, but as someone that has exclusively pugged mythic+ since its inception, I have not encountered the level of toxicity that GD claims exists. Now, I won’t claim that it doesn’t exist simply because I don’t observe it, I could just be very lucky, however I do think there are ways that the community (especially those of us that PUG) can combat bad experiences. The solution, I believe, starts with us, the player.
We need to rid ourselves of the mindset that groups are toxic for not wanting to invite you. People value their time and progress in this game, and they probably don’t want to have it wasted. Given the nature of LFG, there really isn’t a whole lot you can go off of to tell if your group will succeed, other than your IO and how META your class is. This sucks, but it’s understandable. The solution to this, is to build your own community and friends. Yes, that takes a lot of time and effort, but your only alternative is a very shallow system that can only judge you based on your IO score and your class. It is what it is.
You should hold yourself far more accountable for your bad performance in dungeons, and acknowledge that you should improve before attempting higher-level keys. I have seen numerous incidents (especially last season), where we finished 14+ keys with 2 DPS carrying. This is probably fine if you’re friends with everyone in the group, however it seems to lead to a lot of frustration, which I can’t help but think carries over to future interactions. I pugged KSM last season as an Affliction Warlock, and the most consistent comment that I received was something along the lines of “wow, I haven’t played with a good Affliction Warlock before”, this is sad, but probably explains why I had such a hard time getting into groups. It’s very easy to blame a toxic group, however, it seems that in this case it was probably the vast majority of underperforming Affliction Warlocks that were the source of my frustration.
Understand what you need to bring to the table. Tanks are expected to know routes, healers are expected to heal, and DPS are expected to make things die. If you’re consistently putting out 4k DPS by the time the run is over, you’re really not ready for higher level keys. Yes, I understand that different classes and specs perform well in certain areas, however, if your DPS is substantially low, it probably means that you’re not performing as well as you can be. From my experience, and I would love some input from more experienced players, is that 6k-7k DPS per class is probably what is required to time 15 keys. You should probably work towards numbers like this before you queue up for higher 14+ keys.
Learning, working hard, and trying to play your best is simply being courteous to other players. Whenever I perform poorly, I always apologize at the end of the run and thank people for their patience with me. In my experience, it has always been met with “all good” or something along those lines. Perhaps it’s that attitude that has resulted in my overall positive experience of mythic+.