Engaging with these accounts shows that they are unwilling (or else not employed to) engage in good-faith dialogue. Although this guideline applies to all, there's only one "dang" and he can only do so much.
My question: are there tools/plugins/front-ends which you use to, i.e., share lists of known "shill" accounts to filter stuff like foreign state actors out of an otherwise valuable HN thread?
I think you can shame people in a way that isn't completely abusive, and even instructive.
Shame exists for a real reason in communities - but it only works if the shamed (and everyone else) understands why they were shamed. This takes more communication than a downvote ...
But I suspect that tools aren't good enough to reliably work. (Do you want this post, say, marked as FUD because of a negative take on HN posters?)
The best answer I have is to parallelize dang. Downvote it when you see it, and don't feed the trolls (that just gives them a chance to make another comment). If it's particularly bad, downvote and flag. (I'm not sure what the threshold is to kill a comment. It's more than one flag, but it's not that many. I suspect it's in the low single digits. If very many people see the problem, and will bother to flag it, bad comments will quickly die.)
But there are at least two problems with my solution. First, it hasn't been working so far, or at least it hasn't been working well enough. It working better requires a change in behavior (and more effort) from the established users, which is kind of a tough ask. Second, this is something that could be turned against us if a block of zealots decided to mass-downvote and mass-flag things. I mean, we can vouch for dead comments, but that's also work...
Your filters won't work against the new accounts that are plaguing you, and an AI will never be better than people at detecting sarcasm, or be able to sniff out unpleasant states of mind such as nihilism, selfishness etc.
You could create a community of hackers to together censor and weed out questions and comments that aren't kosher, but that group will soon disintegrate with in-fighting, as you will all personally have your strict opinion of where to draw the line of what is acceptable or unacceptable.
So I say go with a smart secretary. He or she will do the job as you demand, and since you pay there won't be any shenanigans or all night debates on what question is honest or bait.
Only a mod can overturn this bias. I've seen it a few times, e.g. people celebrating Queen Elizabeth's death and another where everyone flagged some legit advice from a female founder because "female" sounded like clickbait and sexism. And in these times the action taken was controversial because it ran against community expectations.
Some of the problems you list runs further into the gray area, and I don't think there's much that can be done.
Just use HN for what it is: a stage for performative erudition, and erudite shitposting. Just have fun and don't take it so seriously.
In cases like that, self-moderation works best for me.
I know from experience the comments will tend towards a dumpster fire.
And I am flammable so I stay away to the extent I can by reminding myself there will be another chance to get upset about politics tomorrow.