It would be helpful to understand what you have updated and how long ago you haven’t installed updates.
Arch switched to systemd mkinitcpio hooks, if you did not install the updates long enough it could be the reason. these changes should not be applied automatically, but I still recommend checking this discussion [Unstable Update] November 2025 - #25 by linux-aarhus below are examples for configurations with luks and luks2.
because you performed chroot, I assume that your file system is fine. if you have btrfs snapshots I guess you could just roll back to the point when it all worked (or try boot in btrfs snapshot if you can). Before you follow this recommendation, read more about it first.
These are all the thoughts that came to my mind.