Different pronunciation customs

I happened to encounter several different customs in pronouncing Kimetz, Chulem, etc. Ashkenazi, Sephardic, Yemenite (my mother and my father also differ) – and so on, the whole discussion of how to pronounce words is actually a historical discussion – what was once in the Temple, what is the origin – and so on, talking about reality does not belong to everyone acting like their rabbis, because in this matter the figure of the ‘Rabbi’ has no special meaning, we want to know what the truth is, what was then – and only one is right, – a question – why do we act like our rabbis and not simply clarify the issue, after all some of the denominations have claims, and assuming that it is necessary to verify what the truth is – the rabbis of each denomination – did everyone inquire and come out exactly as their custom by chance?