Don't know about the light situation in FO4, but there was a limitation on the number of light sources that can be used in a cell (without one of them keeps turning off) in both Skyrim and Skyrim SE. That's why they introduced lights that don't emit light. From what I've seen in FO4, int/ext cell transitions still require either a loading screen or an elevator (loads the cell in bg) which is nothing like say, The Witcher 3.
FO76 doesn't even have NPCs, it even seems to have issues rendering neighboring ext. cells, let alone cells full of NPCs running radiant AI, which is probably one of the reasons why FO76 doesn't have NPCs.
BTW, the seemingly increased view distance in FO76 doesn't mean that the engine actually loads all those cells, that's why I mentioned NPCs and critters.
They can go through them just like you, not sure what point would they serve when ladders are rarer than good writing in these games.
There's not a single BGS game that includes ladders that the player can climb, let alone can used by the AI, possibly due to the limitations of their navmeshes. The quality of the writing has nothing to do with their engine.
Something I forgot to mention is that you can't have a fast land/air vehicle in a BGS game because of the cell-based architecture of their engine, having one would possibly turn the game into a shit show. A rather important limitation in my opinion.
God, that video. "I have no fucking idea of how this or any engines actually work, but it MUST be the engine!" Totally not trying to bank on pseudo drama from being mentioned in a single phrase
He defends himself against a false accusation by a so called "journalist" who seems to like sucking corporate dick, why does that bother you?