There's also OpenMW a recompilation project of Morrowind.
Lampenoel
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.
I love playing Skyrim with certain challenges. For example: