And ‘Sinai’ is not a pircha because there is also ‘Shabbos’ and ‘Sorosecho’ that do not fit in with the rhyme-scheme. Furthermore, not all girsas have the ‘loy/low/loh’ and simply have ‘nostato’, meaning that out of 8 lines that supposedly rhyme half don’t. Which I think rather puts paid to your thesis.
History is also not your friend here as Yismach Moshe was written in Bovel where they certainly did not say ‘oy’.