I unironically like the first dungeon of Baldur's Gate II.
It's pretty good. Not sure why so many people complain about it.
What the hell were you expecting? Durlag's Tower 2: Electric Boogaloo?
probably no dungeon at all.
Starting duneons tend to suck, hard, in most cRPGs, even when they're decently designed they still serve to get in the way for repeat playthroughs.
Irenicus's Dungeon is a tutorial, first and foremost. If you've played BG 2 before it's annoying to do the slog yet again.
Doesn't hold a candle to Peragus though. Truly, an absolutely dogshit start to any video-game.