Hello,
1) Please, read here what WordPress child theme is https://developer.wordpress.org/themes/advanced-topics/child-themes/ Because I assume that you don’t clearly understand what is that and mistakenly relate all the issues you have with the child theme.
To change the title just go to Pages > edit Frontpage and rename that. At this moment title of the home page is “Home Jewellery”, so that’s why you see that.
2) Are you talking about filters area https://prnt.sc/219ab7z and large product https://prnt.sc/219ad9q ? We don’t have exactly the same options. So, to implement that you need additional customization.
Regards