It's hard because they write things with intention to upstream it. Omarchy patches simply cannot be, because they go absolutely against the established way of doing things. No one consciously designs anything in their code, it's all LLM output.
I personally vetted that TouchID code you mentioned and it's an absolute hellhole, with everything done in-kernel and no userspace separation what so. That code is also a security nightmare.
In the PR’s that were merged in that kernel I also see they are actively working towards m4 and m5 as well. Must be hard for Asahi to keep up this way.