Short answer:
demons souls + souls 1-3 = magic, pure magic.
Longer answer:
These are not difficult games, I have died more in halo infinite than on souls games. They are as easy as you want to make them, or more like as difficult as you make them.
Be stupid, play stupidly = win stupid prizes.
I have only used mages on these games, so I dont know how much more difficult they are with melee/archer.
But with magic they are really easy.
No need for summons either, mage can kill almost all bosses easily, and even the "difficult" ones arent that hard.
A) add points to intelligence + attunement only until intelligence is like 50-60 and attunement 30-45
B) kill everything.
C) learn to roll around like a mofo, so you dont get hit. (no armors = easy to roll around)
D) dont run around like headless chicken, so you dont get 1 hitted.
E) use items that add magic/damage to magic etc
I played most of these without adding any points to vitality, until really late on the game, and also no armors, just some robes/rags that add something to magic. dagger for those rare situations when "mana" is empty.
Pure sorcerer mage can kill many bosses with 1-3 spells on many of these games, and normal enemies die also with few spells.
With mage, first 10-15 levels are bit difficult, but soon it gets easier and then the mage is half god, just walk around and cast monsters into oblivion.