Hello,
1) To change bg image for this product only, go to edit it with elementor and add custom CSS code – https://prnt.sc/vamn38
.page-heading {
background-image: url(url_of_your_img) !important;
background-size: cover;
}
2) Theme Options > WooCommerce (Shop) > Single product builder > https://prnt.sc/vamocl
3) Theme Options > WooCommerce (Shop) > Single product builder > https://prnt.sc/vamoug
To remove this line from the button https://prnt.sc/vamqei delete the next code from Theme Options > Theme custom CSS – https://prnt.sc/vamr0k
Regards