The standard first 3 R4 keys (control, option/alt, command/win) are 1.25x width while the "true" Mac layout has those at 1x width to prevent the spacebar from having to migrate too far to the right (even though it's still a bit farther right than normal). This means to serve the niche of fn muscle memory users of the niche of Mac keyboard users you not only need the create the custom positional layout but custom keycaps (and the board/firmware you build it with must support layers to do fn in the first place). Then when you do all of this these people will still probably be uninterested because it's not some additional niche design criteria (70% vs 100%, low profile vs full size, split vs not, yadda yadda) anyways. All that is to say, there's a lot more going against it than just repositioning 1 key would seem.

I had a coworker who liked https://mechanicalkeyboards.com/products/mk-lowkey70-black. Basically "an external version of the MacBook keyboard with hotswap switches, RGB, and caps". Dunno that I've seen any full sized variants of the Mac layout though.