So in looking at these pictures it looks like you have a charger or something behind the new watches. I think that’s making them sit way forward on your wrist and making them look much bigger, especially compared to your old watch. The new 45mm watch is 1mm taller, but exactly the same width as the old 44mm watches. The size difference shouldn’t be that noticeable.
Thanks for pointing that out! It’s actually attached to an anti-theft device, which isn’t too thick. May affect the way the watch rests on my arm though.