I fixed the issue. From error_log in public_html/wp-admin I found:
I looked some to see whether it was specific to my livesite, something like indexing, but the error was that I closed my functions.php with a “?>” and there may have been whitespace afterwards that was attempted to be sent which caused conflict. I erased the ending “?>” in functions.php for my child theme and I no longer get the error. I’m not currently completely sure why when I duplicated the livesite to localhost of why I did not receive an error in editing the localsite the same way but it’s possible that the whitespace was removed.