Hestia Child theme creation

Yeah, as you found out you don’t want to edit files directly in your theme because you will lose the changes when the theme updates.

Here is some info on child themes, if you haven’t you should read it.

For your particular theme, it appears the developer offers a pre-made child theme, you just need to download it and install/activate like any other theme. Here are the docs, you may want to look them over.