Hi! Sorry to always be the one to complain.
The Linux kernel on Arch ARM is at 5.8.9-2, while the mainline Arch kernel is at 5.9.3.arch1-1. The ARM kernel release candidate is 5.9.rc4-1, but kernel.org has their release candidate at 5.10-rc2.
I do understand that it's gotten complicated, as starting somewhere around 5.8, the generic kernel had grown so large it could no longer be used directly for the Chromebook builds. There's been some discussion about that here: https://archlinuxarm.org/forum/viewtopic.php?f=15&t=14763.
Thanks in advance for taking a look.