Oh I understand it(well sort of because even Communists can't agree), I've read all theory about Labour theory of value.

Marx never defined the terms about value rigorously, so it can be whatever people want it to be.

I know all about socially necessary value, etc and all hacks people have applied to it over the years. There are tons of interpretations about it.

It still has zero predictive ability in the real world.

Subjective preferences explains where profit comes from with much greater predictive ability. And models real world phenomenon we see.