What makes the later games more approachable? I could maybe see an argument for DS3 being more accessible since it's essentially linear, but at the same time it's significantly harder. Basically anyone can beat DS1 in my opinion, absolute worst case you can wear full Havel's and just facetank everything and flask through the damage. You can poise tank Manus's full wombo combo and just outheal the damage.
I've never been great at rhythm games and I feel like I'm getting on in years and my reflexes aren't going to get any better. Knowing I have no recourse but get good is scaring me off Sekiro. In Elden Ring of course Malenia was a slugfest, I hated Valiant Gargoyles and Godskin Duo. In general I hate gank fights in FromSoft games, they're almost never done well. I needed some time with Hoara Loux and Radagon and Elden Beast was an absolute fuckfest. I played on release so couldn't use Torrent, no idea if that made it better or not.
In DS3 nothing in the base game felt bad, all the bosses felt fine and some of my favourite FromSoft bosses are in there. Dancer might be my favourite but Soul of Cinder is such a fun fight - although way too easy for a final boss. (EDIT: and Abyss Watchers of course.) Sister Friede however almost took my sanity and I never finished the Ringed City DLC because after Demon Princes I decided I needed a break as I wasn't having fun and just never got back to it. I assume Midir and Gael are too hard for me anyway if I struggled with Demon Princes.