Did you make changes directly in the parent theme files (wp-content/themes/xstore) that you are afraid to lose them?
Because I have updated theme (and renamed the old version in case you have any changed files there) and don’t see any problems with styles on your site.
If everything is ok you can remove the old version of theme.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.