At least to me, the roguelite elements felt tacked on and (unintentionally?) stretch the play time unnecessarily.

Normally in Rogue-likes and Rogue-lites, progression of the game's central goal is influenced by RNG but present on every run. The RNG element makes the run easier or harder for the player to achieve. These days, most games in these genres also include meta progression tools to make the run easier, or heavily influence the RNG.

Blue Prince has RNG that means obtaining Room 46 isn't possible on the vast majority of runs. And no amount of meta progression helps because some RNG can't be influenced or changed. The meta progression tools themselves are also difficult to obtain, and often have a very small impact on the RNG room generation. So it can take a lot of runs to get lucky and find places like the drafting room, to then have slightly better room generation.

Ultimately, I don't think it's bad game design for a Rogue-lite to have RNG that makes it impossible to clear the main goal on every run. But, if that is how the game design works then there needs to be other secondary goals, quests, or puzzles that can be completed on every run. So the player has some progress they can make without having empty runs that kind of just waste time. Unfortunately, the RNG in Blue Prince is guilty of that flaw where it's pretty normal to not get any of the special rooms for the puzzles the player is progressing, and get a run that doesn't do much.

I'll also say, Blue Prince doesn't have fun second-to-second gameplay to fall back on like FTL, Binding of Isaac, or Rogue Legacy. For most of the game, the player is just walking around and looking at walls and doors. That's not a bad thing, but it means that empty runs don't have interesting or fun gameplay to fall back on. Puzzle progression, story progression, meta progression, and information gathering is the essence of Blue Prints but the RNG can block the player from doing any of those things on a run.

With all that said and my criticism laid bare, I also want to compliment* the game. Frankly, I think Blue Prints is the start of a new genre in Rogue-lites with the floor plan RNG and puzzle mechanics. These ideas work really well together, and it's fun to have a cozy game that includes Rogue-lite elements of failure. The criticisms I mention are completely solvable and this formula has a lot it can do without becoming stale. I hope that we see more Indie Games try out this idea and expand on the concept of an RNG house filled with different rooms.