Yes. There is nothing EOS-specific here. Even the package eos-systemd-boot isn’t actually EOS specific.
I have never tested it on Manjaro so I don’t know if it would work there but it probably would. Any other Arch-based distro should be fine unless they are doing something exotic.
If you leave the keyfile in place the key used to decrypt your data will be in your initramfs which is now unencrypted in your efi partition. This is highly insecure. In fact, the system won’t even ask you for encryption password, it will just transparently use the key to unlock the volume.
just changed some installs from intel to AMD and see had the intel-ucode still used… because i do not reinstall or update kernels
only exchange the two packages…