If glDisable(GL_DEPTH_TEST) fixes it then it is still Z-Fighting, but something about ya’lls drivers is borked. 
You don’t want to use glDisable(GL_DEPTH_TEST) anyway, it will render ‘on top’ of everything, like if another player is standing in the way or so forth, rather you just want to change the depth test to be >= instead of > (or does MC use <… whichever).