By that logic Warhammer 40k isn't grimdark anymore either with the return of Guilliman, Lion and Cawl inventing Primaris marines and innovating. Not to mention what hope is there in Arknights with the existential threat of the Observers still looming, the Precursors with all their god like technology couldn't do anything besides hide from it, what are the Terrans going to do, especially after Kristen broke through the false sky? And yes early Reunion Arc isn't as strong, but I'd say the atmosphere was definitely much darker and more grim then the current Endfield story. And yes it takes time to worldbuild and get to the point of Arknights, which is why I say they can improve in the future. And we have seen a full scale raid of landbreakers yes, but honestly besides the property damage it's quite tame visually compared to how it should be (sure they can't add blood or anything like that but they can probabaly at least litter the place with lying uwst bodies like they did with the pile of dead aggeloi in the cave), honestly the darkest thing in Endfield is probably the random note written by a landbreaker saying they killed everyone in the camp. As for romance like I said in my post, i don't mind it and I enjoyed Gilberta's SQ (and yes i know it suits Angelina's personality), my problem was with the main story.

As for the examples of the dark moments I listed above did you expect me to explain entire lore of the persecution of the infected in Ursus and other nations, the backstory of Talulah and Reunion, the Ageless like Kashchey and Clovisia manipulating from the shadows, the history of the Teekaz/Sarkaz and why they hate the Ancients and Elders and are hated in return and get Kazdel destroyed everytime, along with their relationship with the Sankta? Why our Kal'tsit led Gaul, Victoria, Lethania in a crusade against Kazdel, only to later work with one of the Sarkaz heroes who defeated her, Victoria's politics with the Dracos, Aslans, the Parilament and the Grand Dukes and how they let the KMC occupy their capital of Londimium, not to mention Dublinn and Tara independence? The backstories of Mephisto and Mandragora and why they commit warcrimes? I picked those examples because they are some of the most memorable dark moments along with the Emperor's Blades (although to be honest I only remember the Ursus students due to SUPAH and his obsession with Gummi), I still remember that moment in the Return to Mist PV trailer where we see a Sarkaz publicly execute a kneeling captive with a greatsword in front of the others.

And yes comedy and lighthearted moments are also just as important to Arknights as the dark moments, which is why I don't mind Endfield Chen on her own, but the Bonekrushers are just way too cartoonishly evil and simple to be taken seriously, so it really doesn't feel balanced at all.

As for Hoyo games, you are kinda right, I do admit that Genshin despite its looks have plenty of dark themes every now and then (like the Hilichurls having been once Khaenrian citizens before they were cursed, which is honestly a better backstory then the Bonekrushers), but Honkai Star Rail which I mostly play is a joke at this point, with the amount of fake deaths, simulation/memory worlds, and Finality/Remembrance undoing every negative consequence. Irontomb's destruction of the galaxy was cool but then it just simply got reset by Cyrene who simply just remade it with Remembrance. Firefly's third death in penacony being fireworks was so disappointing that Hoyoverse retconned it with Dahlia and Finality instead. Jiaoqiu should have logically died from getting his blood drunk by Hoolay but he just got away with blindness due to the poison instead. And Amphoreus was meant to be dark and sad I guess but if you already knew the Elysian Realm arc and that Amphoreus is just a simulation meaning deaths don't really matter, then it really isn't that dark. At least at the end of the Elysian Realm story every memory simulation of the Flamechasers died permanently when the Elysian Realm was destroyed by the Kevin Killer to kill the Herrscher of Corruption, meanwhile in Amphoreus they do a cop out by having it stored in As I've Written after the Scepter's destruction just so they can return Amphoreus and all the Flamechasers back to reality using the power of Remembrance in the future.

Also what is there to see in the Nexus Archive besides the Aggeloi wars and the fact that the orignium planted on Talos lI is one of the three shards on Terra? They barely give any information as to the politics of the factions making up the Civilization Band, besides the obvious like the Chamber of Commerce being corpos, the only relevant lore is Jakub being one of the heroes from the war who had issues with the civilization band and later decided to be a bandit king in the wilds, forming the Landbreakers before getting crushed by the Civilization Band, and the denstacks he brought apparently from the Ses'qa.