I agree completely, meaning it's near impossible to avoid, so I had to vote option one. I think meta-play is pretty foundational to the design of these types of games (as replayable SP campaigns) so if they weren't accounting for that basically being the norm, it would be a major miss on the developer's part.
I think it's pretty distinct from TT play in that respect, and a few other respects as well. For example, if you told your DM, oh yeah I've run this module like 20 times and love it. They might take a few extra days to mix stuff up, while you as the player would be sort of feigning ignorance the whole time about a lot of stuff with the wink, so as not to ruin it for the rest of the players. That's almost like DM helper though, and potentially a bit much.
I think the only way around it would be to build in so much randomization that the player would never be able to step in the same river twice here, but then you lose all the structured bespoke encounters and the DM needs to be like a master at ad-lib in that case.
One of the things I do like about BG3 though is that, even though it's pretty structured and somewhat set in terms of what's there, it still leans into that idea of D&D as spontaneous and tries to be ad-lib friendly, to make that feel rewarding. I think the comedic angle helps with that in many instances. Works better with comedy than tragedy probably, or levity over gravity.
That said, it'd be cool to see them keep running with that concept. Maybe via a game mode that sort of caters to that? As opposed to Ironman, perhaps mode called "ThirdMan" or "Second Time Around" that is more about mixing it up than making it harder per se, if that makes sense, by turning the lights out and then shaking up the grab bag. Since difficulty and familiarity are sort of inseperable here. Or just the DM mode I guess, for stuff on the fly, but I'd still prefer the single player experience for a BG game to have primacy. I guess the Durge run is a bit like that currently.
