I think its just the first time you play these games.
The first time i played Dark Souls it was the most challenging, new genre, didnt know where to go, bosses were dealing a lot of damage, but after you beat the game 1 time you can get used to the genre and finish the others easier.
Dark Souls is not very hard as some people claim, they are however challenging games, not easy for sure.
Sekiro is the hardest, followed by Dark Souls 3, followed by Nioh 2, and then Bloodborne and then Dark Souls 1, then Dark Souls 2 then Demon's Souls. This based on soulslike.
The one game i can safely still say that its hard is Sekiro, all the other were challenging in certain places for short period of time, after you get the hang of it its easier.
Ironically i thought a game like Pathologic 2 was harder than all of them, to survive in the game i had to cheat lol. I mean you can survive without cheating but you get a nightmare ending. It's also the only time i cheated since i became an adult, i used to cheat when i was a kid, i used to cheat Heroes of Might and Magic 3, Commandos, Age of Empires 2 and Doom. Old games, i was a kid in the late 90's, im 28 years old now, so when i was at that age i had no idea how to play properly.
Recently i cheated in Pathologic 2, thank god there was a console and you can tweak difficulty in it, though they warn you it harms the experience, i alwasy tweaked it back when i got what i wanted, if i reach a sticky situation, lol, still cheating but i didnt want to suffer, still i died few times, i dont like cheats that makes you god mode, i only cheated some potions to help the sick people and cheat in the settings of the game to give myself more speed to reach places before time runs out, so the kind of cheat i do is only to see better ending for the game, i didnt want to do a replay since the game atmosphere is so oppressive it makes you feel sick.