Elden Ring is probably the most accessible of them, with a lot more room to just go and do things without crawling through punishing dungeons first. It also has a downright ridiculous number of bosses that range in difficulty from barely more than a trash mob to ludicrously difficult - the very first two bosses you see are pretty high on that scale, though neither needs to be beaten.

There's also considerable QoL changes like the ability to just teleport straight to any of your discovered sites of grace (checkpoints where you can level up, basically) and more resources that revolve around capacity instead of finite resources (a big strength of the series is the whole "estus flask" mechanic where you get X many healing pots per rest so that if you're bashing your head against a boss or tough area you're not burning a resource that you'll eventually run out of or will have to go and farm just to heal, and elden ring sort of expands that mechanic to throwables and a general buff pot).

It still has a lot of the fundamental problems with the other games, like a camera that's one of your deadliest enemies and a bunch of really fucking awful control decisions like aggressive camera tethering and making your dodge happen on button release instead of press, but everything they do well it does as well or better (except for some things in Sekiro, which mechanically made a ton of mechanical improvements that should have been kept on but which were ditched instead).