Kernel won't boot

[moson]

So after chroot, did you run the commands that were suggested in the post you’ve linked above?

Error: file '/boot/vmlinuz-5.12-X86-64' not found you need to load the kernel first

That would mean you have no kernels installed?! Please check with $ mhwd-kernel -li and possibly install at least one (let’s use 5.10LTS): $ sudo mhwd-kernel -i linux510

try that…