Hello,
I don’t understand problem because your site works fine for me. If you use 4.28.1 version of XStore theme use 1.0.23 version of Core plugin.
XStore 5.0 is major update and we have changed a lot of things https://xstore.8theme.com/update-history/ including theme styles.
You use child theme and also made changes that’s why I would not recommend you to update production site now. If you want to try new update then create staging site and update theme and plugin there.
Regards
