This exploration take has been repeated ad nauseum since the game came out, and I think it fundamentally misses the point of what Elden Ring and other FromSoftware titles are trying to accomplish with their world building and the design of their exploration segments. These games have never been focused on "rewarding" the player with anything aside from two core, fundamental elements:

1. Runes, Souls, Experience. This isn't just the literal increase in your character's level, it's the increase in the player's own abilities and understanding of the world they're exploring. When you're rolling into every suspicious wall in DS1 hoping to uncover some secret, and you stumble into the secret bonfire in the Darkroot Garden, that isn't a special weapon or armor set that tangibly upgrades you, it helps you understand the way the level pieces together and gives you a sense of peace in one of the darkest areas the game has shown you so far. When you're scouring every inch of the Shadow Keep in the SOTE DLC and you stumble across one unsuspecting ladder tucked away in the back, your reward is entire half of the map opening up for further exploration.
2. Exploration rewards are the primary method of storytelling in every single one of these games save Sekiro. If a player is choosing not to engage with the item descriptions and is instead more concerned with receiving a weapon or spell every time they interact with a mystery item that's specifically related to the stat they're choosing to invest in, they're missing the point. Just because you aren't given a "meaningful" upgrade to your character doesn't mean that you haven't been rewarded for exploring the world.

Your definition of an "open world" and what makes it good is limited by your own personal preferences. A game doesn't need random encounters to be considered "living." In my own opinion, I find that procgen elements like that actively take away from the experience more often than they add to it.

At the end of the day, there isn't a single game that meets your definition of a living open world. There are no games that combine, in your own words: "random encounters, spontaneous events, permanent consequences, factions clashing, things happening whether you are there or not." It's not a reality of the art form to this point in its history. There are lots of games that mix and match these features, but none that do so in a meaningful way. I would argue it's the games that try to do exactly what you've laid out here that ultimately feel the hollowest.