The Brave A.I. bravely tried... But yes, you should be setting up SystemD boot, instead. Further, it is a lot more steps than listed in that post - which I mentioned earlier in this thread.
Sadly, just installing some kernel and other packages will not automatically restore /boot.
I am pretty firm in the camp that reinstalling the O.S. is your best option. Trying to restore /boot will be tedious and tricky; especially given that youa re running ZFS on a fully encrypted drive.
You were quite on top of your game using CachyOS to access your internal contents which allows for making backups of personal files and data. In my opinion: Take The WIN and run with it.
And a reinstall can be done even more painlessly: