Reverting Boba’s voice to the new version wouldn’t be that hard to do if you want to “personalize” your own ESB:R (both interpretations are good but the original one is far more sinister).
Since Ady is no longer willing to do PT:R I guess we won’t see Temuera Morrison’s face when Boba is seducing the cute dancers.
A) Accents being genetically determined is silly.
B) His helmet isn’t transparent I assume he would like to not like to sound the same out of his disguise as he does in his disguise. I speculated for a while that there may have been a woman in that outfit. Then Leia pinched my idea 😄 (honestly I thought it was Luke’s mum around 1981 for a weird few months)
But yeah better Fett voice is here to stay so if you want to change it back do your own versions.