Malpractice when lawyers perfectly know that they braking laws and does it anyways.
Can't see how this applies to them.
They are just incompetent and cheap.
I was looking at malpractice more from the lens of a physician (doctor).
It's actually all the above and I'll tell you why.
Best practice: offline mode.
In Helldivers I you had offline mode so if the servers crapped out for whatever reason the customer still had access to the game and could play the product offline, single-player. Matchmaking was simply disabled in offline mode, that, and a couple other things.
In Helldivers II there is no offline mode. If you're out, you're out and the customer can't enjoy the product half way at all. They made the decision for always-online with H2 for whatever reason.
Server capacity decision making:
Going into the busy weekend, having the hottest new online game on the block Arrowhead was
apparently still running with server capacity at 360k (which to get to that was a saga in itself). They should know damn well the weekend (that includes Friday past 4:00 pm EST btw) is going to see huge traffic (on top of the viral popularity fueling the game as word of mouth spreads).... Why are you still doing gradual jumps? Say if you jump to 500k for PS5, 450k for PC, and the demand Saturday at 8:00-9:00pm EST burns through that you are still not fixing the problem at all. Whatever ratios of sales/connections that they're using to estimate demand are completely and wayyyyyyy off on top of the built-in lag in decision making to scale up capacity. When your predictions fail again and again the way forward becomes self evident. It's not rocket science. "Bite the bullet" and up capacity significantly... it's not even a hard decision, more like a great investment - consumer satisfaction trumps cost - word of mouth is king, as is maximizing that brief viral window to hook customers tight.
To top it off, they're not new to this game. Helldivers I exists. This game is literally just a AAA TPS version of 1 (albeit with H2 having less content and features than mature H1). Maybe if the studio saw a lot of turnover and shakeups of key people you could say there is a "shock" factor for the "new" H2 team but I don't think that is the case.