there is one thing which is (almost) absolute, aside from a few words here and there. The emphasis of syllables is agreed upon by everyone who knows what there talking about. there is no ashkenazi mesorah to pronounce all words with the emphasis on the 2nd to last syllable. however, this common mistake is widespread.
also, (this one I’m not so sure about), there is no “r” sound in hebrew. the old ashkenazim from europe pronounced the “resh” one of two ways. (i can’t spell it out but you probably know what i’m talking about). And the sepharadim certainly don’t have an “r” sound in their hebrew. the “r” came from american english.