Even 1U alt/ctrl/super/func are left-aligned, but all legends in the three arrow columns are centered. And the FN keys in both Base kits are left-aligned, but in the Mac kit they are centered.
These are all very intentional decisions I made, after trading off the various different compromises with making legends look good together. For the bottom row, consistency with each other is the most important factor. For keys in the paging and arrow clusters, alignment along a vertical axis is more important.
The reason the F-row key legends are centered for the Mac versions is because once you add an icon sublegend they look wrong if the F key legend is still left-aligned, and so I chose to horizontally align them. This isn’t an issue in itself if you’re only using all-Mac F keys or all standard ones; it’s only an issue if you mix and match them which I have to assume most people wouldn’t do.
And in the German Base kit, the FN row's × is centered but the Numpad's × is left-aligned.
You’re conflating two entirely different keys: one is a cross shape novelty key, the other is a numpad multiplication sign. I’ve included four shape novelties in the German base kit at the request of MonacoKeys as these keys are provided on some Keychron keyboards and they sell a lot of keys to Keychron users, so it seemed like a sensible request.
I appreciate that these choices won’t suit everyone. It’s essentially impossible to please everyone at the same time whilst trying to do something new, and not everyone is even interested in the new. I do stand by my choices though, and I’d rather hear feedback centred on practical concerns than stylistic nitpicking from people who probably aren’t going to buy this set anyway.