I love playing Skyrim with certain challenges. For example:

• Survival Master Difficulty with disabled compass and map. It makes the Skyrim wilderness a much more ruthless and immersive place. Or trying unusual character playstyles:
• Get Lydia (or any other Follower) as quick as possible and play Healer only (Multiple Follower Mod recommended
• Play a hand to hand combatant. Good options to make it viable are a Khajiit for the claw damage, getting vampirism for extra hand to hand damage and getting the pugilists gloves. Extremely powerfull, especially if you you choose to play a lvl1-only character.
• playing without any equipment and items (maybe get some unenchanted clothes, so you don’t run around naked). Your best bets are probably a mage build, maybe Bretons with atronach stone for magic defense.

There’s also OpenMW a recompilation project of Morrowind.

Well the Creation Engine and the ID Tech Engine follow two completely different main goals: One is build for wide open spaces and exploration with real time physics while also guaranteeing mod support. The other is build for fast paced combat in closed level structures. And I think especially the mod support is important to Bethesda and its community. That’s also the reason why so many people stick to Minecraft java instead of the more performant bedrock edition.

Like in Immortals of Aveum? I really don’t think that a switch to Unreal is a one-cure-for-all.

And if you are looking for a more modern game, checkout Prey from 2017. It’s fantastic! Also System Shock just got a Remake. I only played its demo but it was really captivating.

I think zelda: botw and totk both fall to an extent in itgat category. NPCs react to the weather, if you are fighting enemies and are giving basic responses about their current circumstances, aswell as the physics interactions that those games allow.