Dropping and joining are a pain, I agree. When 2 join and you’re elbow deep in a horde and a chaos spawn, it’s not fun being 2 players down while they join.
Unfortunately, online gaming is largely populated by the Orange, the Dim, and the Inconsiderate.
Some kind of debuff for consistently dropping when you get downed or dropping as host might be something to consider, but if I get a debuff because someones connection breaks then I’ll be annoyed.
I happen to think blocking people in steam should stop them from joining you(or you joining them) in game, and once people realise they’re blocked by half the world they might consider attempting to be a functioning human being.