Google Structured Data errors

Hello,
I have a question / suggestion.
Upon using the Google Webmaster tools, I noticed that Google is detecting structured data errors, like “missing author” or “missing updated”. I know that both the authors and date are there in the code. So I Googled up for a possible solution. One of the articles I came across suggests there might be an incorrect code in the “single.php” (or similar files): https://www.wpcub.com/fix-missing-required-field-entry-titleupdatehcard-error-in-wordpress/

The steps they outline seem simple enough, however:

a) I am not sure whether I can trust the author of the article (in other words I am worried not to mess things up by altering the code);
b) since I am using the child theme, I do not see the single.php or most other files in the editor. Does it mean that if I decided to follow those steps I would need to activate the mother theme, apply changes, then activate the child theme again? Or could I copy the single.php into my child theme?
c) Moreover, since the theme updates would likely rewrite the single.php file anyway, would I be better off by correcting these errors in the child theme? If so, please advise how.

I think that this kind of generic issues are better be corrected by the developer so that all theme users benefit from it. What do you guys think: could you simply correct these errors in the theme code, so that we get rid of these errors during the next theme update?
Thank you!

Ticket