Start with the one you want to play most. That’s the one that will get you hooked. There’s so many now if you figure you don’t like it you can play another one. The feeling everyone is telling you to chase with starting at demon souls or dark souls 1 isn’t as it was back then. I play through them every other year and its fun but the grand reveal on reality has been had and is done. My favorite souls like I have played recently is Hellpoint, it can be janky and doesn’t hold your hand at all but I love it.