There's punishments for leaving Dynamax Adventure online early. Thank god.
Though it is annoying that they'll disconnect, I really don't see the point in doing so (unless it's accidental). Even if you go in to the last battle with a far-from-perfect lineup and moves that clash, odds are you can still pull through if people work together and avoid being dumb.
That's basically life. Things will rarelyu go the way you've planned, but that doesn't mean you should give up. You just have to work with what you're given, and you can still succeed without having everything go perfectly.
So after 5 failed attempts to defeat Palka (including one gem of frustration where one of my teammates basically threw by setting up Electric Terrain with his Klang's Max Lightning, preventing my Jynx from using Lovely Kiss to put it to sleep and allowing us to defeat it the way we defeated each of the previous bosses) I decided to just go with AI partners, where I would get to choose what path to take and whether or not to swap my Pokemon at will.
Got Jynx (possibly the ideal Pokemon for defeating Palkia thanks to Dry Skin, Lovely Kiss, and Draining Kiss) as my starter Pokemon and defeated Palkia first try with AI partners, after failing 5 attempts with real people. I'm not sure what it is about Dynamax Adventures that compels some people to turn their brains off, but it is frustrating at times.
That being said, not all of my experiences have been bad; in fact the majority have gone quite smoothly. When they don't go smoothly, though, it can be very frustrating.
I don't think that was so much a "throw" as much as it was just someone playing like an idiot. This is essentially how things go for any cooperative thing you do: There are people who just aren't team players. They don't know how to work with other people, they think they have all the best ideas and expect everyone else to follow, and they just charge on ahead without thinking. Some of them know they're not team players, and some of them think they're hot stuff and a born leader, but their effects on their teammates and their overall performance as a group are the same. In the case with that Klang, likely they used Max Lightning because it was the move with the highest base power they had, and they didn't know nor cared you were going to use Lovely Kiss. As far as they were concerned, you were their backup, there to do some extra bits of damage for them.
I had a teammate who took ages to make any move in a Dynamax Adventure, and when they did, they more or less selected a move at random without concern for type effectiveness (or if it would even work at all in the context, like Normal-type moves against a Ghost Pokémon), then eventually decided upon a move and would use it for the rest of the battle. They also chose to accept every chance to swap a Pokémon out, even if someone else really needed it or they were fine without it. The other three of us basically carried them to the last battle. Then, early into that battle (I believe it was Dialga, but I know it's something weak to Fighting), this player underwent a Jekyll-and-Hyde flip in playstyle. Suddenly, this player made moves really quickly and made smart decisions, and we beat the Legendary Pokémon at the end quickly and decisively. I suspect this was actually two people: One was very likely utterly confused and didn't know what to do, while the other was a lot more experienced and better at the game and assumed control. If not for that flip in behavior, I would've assumed a bad connection and maybe an unresponsive controller (which can happen when it's dangerously low on battery power), but at that point, I was pretty sure if WAS someone at the helm who had no idea what they were doing.
It's not that Dynamax Adventures bring out the fools in people. These people have always been fools, but now you have to work with them.
It's not even just Pokémon, but any sort of activity that requires working with a team. Coaches for team sports turn down athletes who may be amazingly skilled but can't get along with the other players, and they encounter them all the time. And those contestants on reality shows who immediately try to be the leader (and may mor may not succeed at assuming the role) and make bad decisions thinking they're geniuses do exist. (I'm reminded of someone in the first episode of
Race to Escape, who wanted to be the leader, and everyone else let her. She made all of the decisions and gave out orders to other people. She only allowed the team to do what she planned. They failed their goal because someone else had the correct idea, but she refused to execute it because it wasn't her idea.)