The only Metroid games I've beaten are the three Prime games, and probably the hardest games I've ever beaten are Ori and the Blind Forest and the SNES Donkey Kong Country games. I'm willing to watch guides and to keep trying if it takes me several tries to beat a boss, it's just people are hyping up some of the later bosses and EMMI sections as major difficulty spikes and I am not the most skilled gamer.

The EMMI sections really aren't that hard IMO. If you've done them already, they really don't get that much harder. Some of the later EMMI have attacks that can stun you from a range, but the same basic principles apply. If you take your time and act carefully you'll be fine. Or, if you're impatient like me, you can plow through the sections at full speed. You'll die a few times, but within a few minutes you'll get through, and dying generally just sends you back to the beginning of that sequence.

When you actually fight the Emmi, it's more like a puzzle game then an action game. You just have to find the right spot to ambush them (generally the longest hallway available) and as long as your aim isn't complete shit, you'll be fine.

The bosses are kind of tough towards the end. the last one in particular. But, none of them really require amazing reflexes, just good pattern recognition skills. Again, I'm an impatient person, but I think if I took less risk and focussed more on dodging than firing, they would have been not terrible. I haven't played Ori and it has been a long time since I beat Prime 1/2. IIRC the bosses are harder than Prime's, and a little bit more than Prime 2, especially if you played it on Wii. The SNES DKC games were actually kind of tough. Not so much the bosses, but I feel that if your reflexes are good enough to handle the tougher levels in Country, you should be capable enough for this.

I agree that by the 4-5th area EMMIs became more annoying that anything else but Samus is so mobile by that point that I mostly sped my way through their section with no care if they spotted me or not.

I've seen a short clip of someone having the Screw Attack earlier than regular so I think sequence breaking might be possibe to some extent.

Sequence breaking is definitely a thing.  There's an any% run on YouTube that's 1hour 55 minutes (cutting out the cutscene times) 

Bosses have always been like that, though. In all other Metroid games before you'd have to learn the patterns and figure out how to react to their attacks. Every player who faced any boss in, let's say, Super Metroid gets their ass kicked hard, but once you've learned their behaviours they become pushovers. It's the same in Dread. Once you've learned to read the moves you can beat any boss without even a single hit. So I don't get your point, sorry.

And Other M belongs to the mainline, it's right in the middle between 3 and 4. It's a hard to swallow pill, I know. Just let the dissapointment go, it's ok.

Not having ending variations I agree, that's a bit sad. And I would have loved the ability to crank up the music volume, I think it's not loud enough.

You know you get two chances to counter an EMMI. The first one is totally doable, I get it every second or third attempt. But the second one is near impossible.
But I managed to do it after like 30 attempts and it's the most satisfying thing ever and looks so cool. The animations in Dread are fantastic.
At first the EMMIs were terrifying, but now it's kinda fun getting caught on purpose and countering them.

In a half hour stretch just I got the wide beam, killed an EMMI to claim the morph ball, beat an escape sequence and gained the Varia suit, and the whole time I just always ended up where I needed to be, without ever being given an objective marker, simply through utterly brilliant organic level design. Not a minute felt wasted, I was constantly making progress, exploring, growing stronger.

This game is freaking incredible.

Are people not utilizing the counter and Flash Shift in their fights? Bosses are hard when you first come across them but the moves they use are telegraphed meaning when you see the sign that a particular move is coming the are a few responses to it to do straight away, the best move the game gives you is Flash Shift as not only can it give you an escape route it can be used to set up offence and it's effective in doing so against multiple attacks this becomes even more powerful once storm missile is obtained. You are meant to die in fights as the game expects you to do different things to figure what the best response to each move is hence why it has checkpoints for boss fights, identifying attacks that can be countered is also key and countering moves leaves the boss wide open and in triggered counter sequences deals more damage that you can in open play.

Personally I think it's great, Dread is very much an evolution of what was introduced in Samus Returns (another fantastic game). I love how Its challenging but not unforgiving, I've lost track of how many times Samus has been stabbed in the head by an EMMI only to r1espawn at the other side of the door. Im genuinely enjoying this more than the Prime games but I suppose its each to their own.