How accurate is the Chernobyl miniseries on HBO to the actual events ? Was the negligence of Human life by the Soviet State and it’s members this bad ? Was the higher-ups of the Plant as depicted in the show ?

Chernoyl by Serhii Plokhy is an excellent resource for this. I've only seen the first episode but I can tell you it had some inaccuracies. One, it wasn't as readily obvious in the real world as it was in the show that radiation was so high at the scene. People's flesh didn't *immediately suffer radiation burns on contact with graphite and it actually took a few hours (enough to put the roof fire out) before it was clear that people were suffering from radiation poisoning. Additionally, there was only one firefighter who looked straight into the reactor, the first confirmation of the reactor bursting for anyone making decisions wasn't until they flew a helicopter over it early the next day.

There's lots of little things but I actually applauded the show for its emphasis on it being a human caused disaster. I especially liked the "3.6 roentgens" thing making its way all the way to the top; this kind of stuff did happen. There were shortages of supplies and oversight all through the already rushed build job of Chernobyl and it had a very real impact on data collecting. Additionally, the USSR's power structure made it so no one was really willing to take responsibility for things, so for most people they felt safer just waiting until someone higher up came.

There was a big emphasis as the crisis unfolded on "preventing a panic" among the Ukrainian and Soviet citizens as well as keeping information from disseminating, to Soviet citizens or the Western nations. It was so bad that the Party insisted on parades to celebrate International Workers day in cities that were experiencing record radiation exposure just so they could "prevent a panic."

I can't go through all of it but I think the show's point is to emphasize 1) people's reactions to what appeared to be a life ending disaster on an unforeseen scale and 2) the inherent shortcomings of the Soviet power structure and how it affected decision making. In that respect, I think it does a good enough job.

Edit: Fixed some wording.

There are inaccuracies, but they serve largely to enhance the show, with some exceptions that I intensely dislike as they border on fear-mongering.

As /u/MaverickTopGun said, the idea of getting horrific burns that cause your flesh to fall apart in mere minutes is heavily inaccurate (though the 'nuclear tan' was real, though I'm not sure if it actually appeared in mere seconds of exposure)

Some other inaccuracies:

Chernobyl wasn't belching out clouds of thick black smoke. The black smoke was caused by the roof fires which were extinguished on basically the first night. After that (you can look up satellite and site photos of the accident) the burning reactor was only releasing a thin white vapor. The reactor wasn't "burning" fuel, so there wouldn't have been any carbon to be causing smoke like that. The reactor was releasing enormous amounts of invisible radioactive byproducts. This video was filmed on 28 April, two days after the accident. Notice there's no black smoke, only some vapor. You can see into the molten reactor, it's mostly just glowing red-hot... because it's hot metal, that isn't combusting anything.
The giant spotlight into the sky like it's the Luxor pyramid... there was reportedly a glow, but it certainly wouldn't have extended that high/far due to how rapidly radiation diminishes due to the inverse squared law. Additionally you probably wouldn't have been able to see it during the daytime (as you do in episode 2).
A few tiny inconsistencies like three people went in through the door that Yuvchenko held open. It's also not certain if they actually looked directly into the core. If you look at the size of the reactor hall and extent of the damage it's highly unlikely they were able to actually see into it. They were, however, crawling around in debris that was full of graphite and fuel. All three died extremely quickly. Yuvchenko survived, and his injuries (except for the instant bleeding and collapse shortly thereafter) were largely accurate. It was caused by the door to the reactor room being covered in radioactive soot and being in extended direct contact with it.
In the second episode they show a helicopter crashing into the crane while dumping boron silicate into the reactor fire. This helicopter crash didn't happen until months after the accident (accident was in April, this crash was in October, six months later).
The Red Forest took weeks to turn red as the trees died from the radiation exposure. The show depicts it happening literally overnight.
The "bridge of death" in the first episode is total fiction. This is probably the worst offense. The show doesn't tell us that everyone there died, but it's heavily implied by the 'fallout' raining on them that they're all getting intensely irradiated. It shows a thick ash, like snow, everyone is playing in. If that ash was even mildly radioactive, everyone there would be dead. But there was no bridge of death. Nobody in Pripyat itself, that we know of, died from the fallout of the reactor fire. There was, in fact, no ashfall or fallout on Pripyat. The radionuclides were invisible and microscopic. Like I said, there was no giant black cloud of radioactive smoke and debris pouring out of the site. EDIT: In episode 2 they show civilians with 'melting skin' (the guy with the baby). I'm pretty sure we're supposed to believe that these were the people on the bridge. I don't believe there's any record at all of anyone in Pripyat getting radiation poisoning severe enough to cause that extent of injuries. I can only presume that this guy was on the bridge, and the bridge was total fiction, so the burned civilians in the hospital would also be fiction. CORRECTION: There is one well-documented civilian who was sick from the accident. Petr Tolstiakov was a fisherman near the reactor that morning, fishing in the warm water coolant runoff from the plant. He stayed and watched the fire from the explosion and got mild radiation sickness. He was, however, obviously MUCH closer to the plant than the city of Pripyat was.
I don't know her name, but the lady from the Belyarussian Nuclear Institute (or whatever it was) isn't real, she's a composite of several scientists. Almost everyone else in the show is real, though I would recommend watching with subtitles, because it can be hard to pick up names. I wish HBO had a guide like Amazon Prime does where I can see who is in-scene, the reactor workers can be hard to tell apart since they all dress the same and the lighting can make it hard to see who is who.
I can't find any evidence of a firefighter who directly handled the reactor moderating graphite and had his hand disintegrate.

So, the show does have a lot of inaccuracies, most of which are done to enhance the show. The thick black clouds, for example, serve to illustrate the dangerous waste in the air, because otherwise we wouldn't be able to see it, and the show would lose tension. I expect the inaccuracies to accumulate as the show goes on. I expect that a lot of this is done to make the accident look more horrific than it actually was. That isn't to say it wasn't terrible, but there tends to be this kind of mysterious aura around the Chernobyl accident and people tend to believe that thousands of people died and radiation was causing people to melt... it doesn't really sell the drama if you just showed a nice Ukrainian spring with blue skies, where most people just get mildly sick and nauseated, and then recovering and going on to live their lives normally. If you look at the known death and injury toll of Chernobyl, it actually is a surprisingly small list compared to what a lot of people likely expect.

EDIT: Also in the second episode they claim that the radioactive lava hitting the water would cause a megaton-scale explosion. Absolutely 100% laughably fucking wrong. It would have caused a second explosion probably no worse than the one that blew up the core in the first place, it only would be worse because the core was already breached and thus easier to throw more radioactive fuel around. I forgot about this one. Like I said, I think there's a bit of fear-mongering underlining this show.