You should know that all the m4 variants share the very same hardware, so all the software is common among themWait, I saw the compatibility of the TWRP and there was no mention of support variants E2306, so which TWRP did you installed? If this is true then yes, I go with unlock bootloader but I stuck on incompatibility of the TWRP, but look like is working, right?
Also my device was a e2306, and I tested on it so for sure it will work flawlessly on your device