Funny, because DS1 is one of my comfort games. I play it to relax. It's hard to explain. One of the things I love about the Souls series in particular is it's one of the few games that I know isn't bullshitting me. If I die, it's my fault. So many other games seem to have mechanics that are meant to assist the player, which in my experience does the opposite and makes you confused about why you died. This leads to frustration. DS1 is the exact opposite of that for me.
I can get that, and I also get that some players feel a sense of achievement when defeating a difficult boss. I think this is a larger reasons for why these games do nothing for me. My brain doesn't function this way and I have never felt any sense of relief or achievement when beating a difficult boss or encounter. The reward isn't there for me so instead it is just a slog and timing mechanics which is something else that never syncs with me.
I am the same way with loot games like Diablo. My mind instantly sees the treadmill and the grind for gear doesn't interest me. I want to love the games and will for a while. I just very quickly hit the wall where I see behind the curtain and can't ignore it.