Reading the enemies archive in the game I think it’s extremely important to remember not all Hilichurls are from Khaenri'ah, noted by Hilichurls description.
“Their presence on the continent has been recorded for over a thousand years, and yet they have neither history or civilization.”
They only recently began producing more after the whole incident in Khaenri'ah. Looking through the game text I don’t think there was ever any mention of any other nation begin turned into these guys which is weird if they were here for thousands of years. Another weird tidbit about them is the Anemo Hilichurl Rouge.
“It almost seems as if they are searching for the fated genesis of their kind, seeking to uncover some bygone splendor that once beglonged to their people.”
Of course this could absolutely only refer to Khaenri'ah as “seeking to uncover” but it could also be meaning another past in Teyvat’s history that’s yet to be discoursed yet. And their creator wouldn’t make sense for Khaenri’ah as they would already know who they’re looking for since it was Ronova who placed the cursed on half-Khaenri’ahan’s so wouldn’t they just go to Natlan since that seems like the easiest way to contact her. Personally I think something else maybe other than the Heavenly Principles could have made them.
Also remembering Caribert at least not all but the Hilichurls who are affected by Ronova’s curse by some weird medicine can regain their speech and humanity. Which also begs the question are the ones that Ronova cursed and other Hilichurls different species as in they look the same or are different in the way of how they can retain their humanity or are they the same and any Hilichurl can regain their humanity by that weird medicine Chlothar made.