The difficulty is really overplayed IMO. There's a lot of permanent progression for solving puzzles, so as you get to the harder puzzles you also have a much easier time with the roguelike portion. There's also a ton of stuff to figure out, so you're very rarely only working on one thing.

Side note, 90% of the people I have seen saying this are redditors and it's really exposed me to how bad some of the Gamer types are at videogames

Idk if I’d call it fatal. you have a lot of threads to pull at, I feel like the rng doesn’t matter.

I suppose if you’re almost finished and just need the stars to align or are trying to resolve a single theory it might get frustrating

Yes.

I understand rng is a thing in roguelikes. I am at a point in BP where I know exactly what to do and how to do it, to get to the next phase. I have not had luck with rng in getting the room layouts needed to get there. It's the one thing that's really tainted a pretty cool game so far.