My vote for most confusing layouts are Edinburgh Waverley and Stratford. I haven't been to Edinburgh for quite some time, and in October 2020 when I was last there it was basically off the sleeper, into Nero and out of the station, so I wasn't too affected by the crazy layout. Other times, when I've been there red-penning stuff, the platform layout would always catch me out and I always struggled to find my way around.
Stratford, well I can't remember what my actual journey was now, but when I was last in London on a red-penning spree I found myself in Stratford. Whichever way I was going, all I remember is that it took me some time to find the way I wanted and a double-back.
I'm sure for regular passengers, they're both easy enough, but for infrequent visitors they're not fun. Birmingham New Street I have no issues with, I can see why it would be a bit 'where do I need to go?' to a visitor though. It's a station I've used many, many times so it's not too bad for me. I can make a connection from platform 10B to platform 3A in less than 3 minutes, I think I could do it in 2 minutes if I had had less people in front of me!
Another one I'm not a fan of is Leeds, it does take some navigating if you're not too sure where you're going. The lowest numbered platforms are the worst for that, I've come very close to missing a train from there in the past. Not quite as confusing as Stratford or Edinburgh though!