I’m no Brian, but I did talk about UBoat a bit on QT3 over here.
The crew and sub management stuff takes some learning but I would say it’s just the right amount of finicky. When you surface the boat you have to remember to switch from electric to diesel, to cycle the air filters, pump the bilge, maybe change the below decks light setting and maybe restart the compass but the actual doing of all these things is pretty easy.
I link video series over there that essentially replaces the in-game tutorial and it’s worth a watch if you own the game.