I've been playing a lot of SM2, completed the campaign and doing tonnes of the extra mission Operations mode. No PVP, I'm too burned out from years of LoL to bother with that anymore.
My TLDR is that I like the game, but if you don't like parry/ dodge/ mob combat like the recent God of War games, but with a shit-tonne more enemies, it will just piss you off. It also hasn't got more than maybe 10-12 hours of original content if you do things on the easiest difficulty, and only play each Campaign and Operation mission once. There is diversity added here, but it doesn't affect anything, so I don't care. I just turn the helmet option on as helmetless is dumb anyway.
My thoughts are it's not complete, there are a few things missing that require addition or tuning:
The campaign is alright, it suffers from mission bloat as the last one really is about 2 missions in 1, turning it into a slog. There's a lot of great spectacle, but it can wear thin. Titus is a good all rounder, but on the harder difficulties you do feel like a bitch, everything just does a shit tonne of damage, and Zangor's with shields are honestly ridiculous as enemies. Also termagaunts are crazy overpowered. The AI companions are Fine, but on higher difficulties they won't do anything of value. There are a few glitches here and there, mostly some visual, some frame slowdowns, one had me back out of a menu too quickly, and my PS5 screamed in agony, none stop, forcing me to quit the game as reloading and exiting to menu didn't fix it. This happened three times.
Operations mode is what I see as the meat and potatoes, you can select a class and specific weapons, then upgrade them, requiring tokens from harder difficulties. You get new bosses and mechanics and the AI companions, while dogshit, can get you through the 1st and 2nd difficulty levels. 3 and 4 really require other players, and currently matchmaking isn't an issue, though the load times seem really excessive as it 'finds a server'. I note it does this on offline mode too, and it is also prone to just forgetting to save hours of data, so you find yourself just back where you were. No idea what caused that but it was very annoying. Your mileage will vary with A) if you have friends to play it with, B) how invested you are in levelling up the classes and weapons C) how good you are at the game because other players seem to have a low skill ceiling for the most part. Frustration can come from playing with randoms who are useless, as there is no barrier to them joining higher difficulty missions and dragging you all down.
If you like the combat, the game will have a lot for you, if you don't, then don't get it.
It has one of those systems where you can't avoid damage, but you have to fight and engage with parries, or dodges and executions and the little gun ripostes to get your armour and health back. It does lead to moments where a bunch of shitty hormagaunts just chase you down and whittle your life away with no recourse for certain classes. Zangors again can eat shit, those things have infinite combos and just follow you forever. Certain other enemies have bullshit moves, Carnifexes can't be parried and attack none stop, Lictor's have a few BS attacks and seem to appear at the Worst possible moment. Zoanthropes are dogshit unless you have a sniper to mulch them immediately. Terminator enemies have a (as far as I can tell) infinite machine gun attack that only ends if you break line of sight - you fight them in open arenas most of the time so this can be frustrating.
Parries feel good, although it still requires learning some enemy attack patterns to actually get ripostes. Some enemies will bait a parry with the blue symbol, so you block the first attack, then follow up with another couple that also require parrying before you get the gun riposte and stagger them. Normal attacks can all be parries. Red attacks require a dodge, and again, some are timed so you see red, you dodge, you win. Some are that you see red, and about 4 seconds later the attack requires a dodge. This just means it isn't a braindead button masher.
For the diversity debate, the main campaign has Titus team up with an asian and a black marine, under the watch of a bald ginger Scottish marine. If this bothers you, then skip the cinematics and turn the helmet option on while playing in-game. There is an asian/ tanned woman with a Russian accent for the Cadian general, who appears for about 2 minutes of cutscene time, she's fine. While the lore doesn't suggest any issue with them being recruited, Ultramarine's are son's of Primarch Guilliman, who has notoriously strong gene-seed. This means they all grow to look like him - but this is often glossed over in the books and with the models. The multiple races has likely been done for diversity purposes, but nothing is done with it, there is no preaching or pandering.
Titus is made out to be totally in the right throughout the game on every subject, with the asian marine questioning him and accusing him of being a heretic. This causes the two to come to blows and the black marine backs up Titus, siding against the asian marine, who then comes to his senses and apologises later. Other than seeing other races, there is no political message here, and in the context of the universe it is set in, it's not that egregious.
I like the graphics and art design, very pretty and interesting. The marines all look great as are the unlocks and weapons. The enemies all look great, and are responsive to fight for the most part. It does get a bit annoying when your character does an execution and it randomly picks a longer one. For instance a hormagaunt jumps and you and you parry with a hammer - the best option is your character grabs it and flings it on the ground in a second. The worst is your character hits it with the hammer, kneels over it and smashes it again with the hammer for three seconds. It's just annoying.
I'd rate it a 6/10 at the moment. Very expensive for what you get, probably very frustrating if you don't enjoy the combat or aren't great at reactive gameplay like that.
Comparing to other 40k games like that Rogue Trader one, that has a lot of the world building and atmosphere, a lot more customisation and a lot more content, but it is another genre. I would 100% recommend that for RPG/ Turn Based enjoyers, or Mechanicus for much the same. Mechanicus has the better combat and a killer soundtrack. Both are 10/10 from me. The Grey Knight game as well is fine, I'd rate that a 7/10 as despite being years old, it's still buggy and unbalanced, but still worth the price on discount. That too is a turn based.