I use Windows for work and play, but use the Apple M3501 at work. The OS key is mapped as the same OS key in Windows so it's functionally identical. I would say I struggle more from switching to the Apple AEK profile to SP SA. The bottom row is also different in number of keys and length of each key, but I don't seem to have any issues with that. I would love if my work keyboard had smaller bezels.
I can see just cause for "improving" the standard layout; however, I don't see the real value in these micro-improvements. The left side of a keyboard is a mix of 1u-2.5u keys. So the only key that can be shrunk without really changing the layout is Shift. What would you add in the space granted by shrinking the shift key? I can't think of I key or string of keys that I use enough to justify it's own button. Same goes with a split space. I like how big it is because I do use both of my thumbs to press space (mostly the right now that I am thinking about it), but more because I strike the space bar from multiple spots as I type, which is probably "incorrect" but feels better. Forgiving. On a ANSI full size there are 4u of space above the numpad that is unused and 5u worth of space around the arrow cluster that could be used for Macros/Shortcuts, etc vs modifying the existing layout.
I work T2 IT so my job doesn't involve lots of shortcuts, it mostly involves writing notes, a few shortcuts for screenshots, opening Windows apps, etc. What kinds of jobs benefit from the increased flexibility and shortcuts and how much time/effort does it save? That level of min/max seems more balanced towards: this is technically faster/easier and is fun more than it is to actual efficiency gains. But at the end of the day keyboards are a means to an end and we are just tryng to express ourselves or have a good time while doing it. I'd love to hear some real world use case where these "micro-efficiencies" are measurable benefits.