A couple more observations, may be it will help someone.
Text itself(without the signing part) has all letters from the alphabet except for j:
OkhersaBTCpuzlqinfwgymxvd
also if we remove repeating letters from Natasha Otomoski / Satoshi Nakamoto we will get:
123456789
satohinkm
123456789
natshomki
But at this point it feels like trying to find meaning where there is none
May i ask what the numbers means when you convert character? I don't understand what it does to the answer, do the passphase contain numeric charcaters? All i know so far is the private key was sha256 of the passphase