On macOS, IIRC the userspace and kernel-space page size can be different and different userspace programs can run with diferent page sizes, however on Linux the page size is currently fixed across the system and set at compile time. The M1's IOMMU only supports 16k-aligned pages, so memory regions that need to be shared with other hardware (e.g. the GPU) need to be 16k-aligned. As such (and because Linux doesn't currently have great support for mixed page sizes), the Asahi Linux project has decided to run with 16k pages globally. However, that breaks a number of applications that are expecting 4k pages.
More info: https://github.com/AsahiLinux/docs/wiki/Broken-Software
That means a lot of software has come to assume that.
Certain memory buffers need to be page size aligned, or a multiple of pages long. Code can only be loaded to a page aligned memory address. Memory mapping and read/write/execute permissions can only be set on a per-page basis.
If all that stuff is hardcoded now, there will be lots of fixes necessary to make things work properly with a different page size.
And those fixes probably will need the software to be recompiled. And some software is only distributed in binary form, and getting someone to recompile it may be nearly impossible.
I think that Fedora may be leading the pack here, see https://danielpocock.com/power9-aarch64-64k-page-sizes/