I don't know about your specific issue with Foundation.framework, but regarding "
Apple doesn't support (and strongly discourages) statically linked executables[1], so it's not terribly surprising that this doesn't work." I think you're interpreting it a bit more broadly than intended.
Apple's point in that tech note is that you shouldn't statically link what most people think of as libc (called libSystem on macOS). You can statically link anything else because that's basically just you deciding how you want to organize your software. The reason for this is that libSystem is where the kernel syscall wrappers live, and they don't want you to make syscalls directly because they don't want to commit to a particular kernel ABI. That's why they don't ship a static libSystem or any of that crt0.o stuff, but if you have a ton of .a libraries you want to link into your executable that's fine because it'll still be linking to libSystem.dylib when it wants to make syscalls.
The only mainstream project I know that actively ignores this advice is Go, which has implemented its own syscall wrappers for macOS and as such occasionally gets weird bugs when Apple makes changes to the kernel ABI.