I think you made the right decision by swapping out. Before your acquisition I was going to say that if there was zero shot of you buying another watch in the future, then I think the AT is clearly the better all purpose piece.
However, when you consider the value of a 300M right now (no better deal for your money except for maybe a Black Bay), my recommendation was going to be the GM now and start throwing a few dollars for a diver as your sports watch. That stunning 300M white dial on a black strap can be found for ~4k. The blue and gray dial even a few dollars less.
I think the GM for work and going out whilst having the 300M for play would be an ideal 2 watch rotation. I just wish I could spend my money as easily as I spend yours.
Either way, beautiful piece and congrats on saving over 3K compared to datejust! (Not hating, I love the white dial and wimbledon DJ).