DS3 is harder than the rest simply because the combat is quicker and the enemies are full of cheap combo moves. Honestly gameplay vise my favorite is SotFS followed closely by DS1 remastered with DS3 being a distant last. Lore vise though I don't get the hate some people had for DS2. Yes, it does its own thing and isn't a direct sequel and yes it's not as good story vise as DS1. But it's still a bloody solid game that beats almost anything on the market other than the original. And it really didn't deserve all the hatred it got.
I can't pretend to know for certain. As I've only played some of Bloodborne. (And Lords Of The Fallen, which is regarded as one of the worst Souls-like.)
But wasn't DS1 Remastered, generally fan regarded as a cash grab, in that it barely changed anything for a full priced remaster? (Things like frame rate and minor graphical improvements that were done by the mod community already.) And yet it made certain things worse than before? Like added bugs that weren't in the game prior.
And similarly, I'm pretty sure Dark Souls 3 was made purposefully more accessible by its developers. (Maybe in contrast/backlash with how much they played up the "hardness" of Dark Souls 2 for marketing.)
And I don't know if "Lore" was the main reason anyone likes the Dark Souls games, but I don't think "Lore" was Dark Souls 2's problem. After watching videos from Mauler to Matthewmatosis, and plenty of others, its seems that Dark Souls 2 (and its own DLC) had plenty of things to dislike about it.
If you're actually curious to "get" why some may dislike it.
I've played and enjoyed my first few runs of Hades. Even if the first two deaths were related to me straight up not knowing the basic controls and mechanics. (In part due to my Switch Controller's switching/fucking up the normal buttons.) Yet still, it involved my character taking most of my damage from its traps. (By accidently rolling into them.)
Though thus far, the method in which it assures your death, feel a little cheap. (Like how it seems very unlikely for anyone to beat the first boss of the game, without first gaining access to the double dash ability that you get after you first lose.) Thus, immediately trivializing her attacks and difficultly thereafter. So, less of it is me "getting better", then the character gaining RNG abilities that break the challenge. My last run getting simple/low damage 'distant piercing attack' from my sword. But this alone made me dominate the fights and one-shot bosses. But with how health and healing works in the game, and how it feels artificially difficult to get. It really heightened the general feeling of "You're not actually that difficult at all. And if I could actually heal, you'd be dead."
So I hope that sense doesn't remain true later on.