I figure this might be controversial but I think each game gets worse although introducing some cool things and quality of life improvements.
Dark Souls 1: Perfect combo of clunkiness and agility. Perfect interconnected world. The most memorable moments for me (first boss encounter, get lit up on the bridge, the Taurus demon, the Gargoyle fight, etc).
Dark Souls 2: It has cool open world, cool characters, and interesting mechanics.
Dark Souls 3: Impressive visuals, quality of life improvements like re-specing. The combat is too fluid though, the enemies too easy to stun-lock kill. too much endurance and I think spells are overpowered but maybe they always are?
Elden Ring: Interesting open world, interest alt-lore, some good quality of life improvements. Maybe could have used a randomizer for item placement for replays? I felt the game looked and played weird to me.
Obviously, one of them being the first you played could sway things. DS1 was my first, DS3 was my 2nd, then Elden Ring and then DS2 for full disclosure.