cannot boot. volume disappeared from boot option after Disk Utility (GUI) repair
You managed somehow to kill your EFI. (EFI is the boot loader)

EFI is in a Hidden partition on your hard drive. 

Obviously you found it and kill it?

Just to say, in reading your activity, you do mess around to much.

Macs do not need regular maintenance specially not using Recovery mode.

You can get help from here to get a copy of the EFI.