Macbook Pro 2011 : After disabling the dGPU using Arch, normal boot hang halfway but working in safe boot
The problem that you're having is that you're not quite following the instructions correctly. 

More specifically, you've run the diskutil cs list command correctly, but the purpose of running this command was to identify the Logical Volume UUID. And, the reason you needed to identify it was because you need to actually use it in the next command. 

In other words, instead of entering:

diskutil coreStorage unlockVolume UUID 

you need to enter 

diskutil coreStorage unlockVolume 3F7CB47E-F743-4DBF-9BF1-10E574F85D13

instead.

NOTE: This answer is designed to clarify how you needed to follow the instructions you're following. As your question only quotes a portion of those instructions, I cannot directly vouch for the accuracy or validity of the full instructions you're trying to follow.