1) To show the percentage sale label on the single product created single product builder enable it in Sale label settings https://prnt.sc/1v4pd7b
2) You use third-party Additional Variation Images Gallery for WooCommerce plugin that replaces images block with the mentioned label. Our theme comes with the built-in variation gallery feature. Why do you need third-party plugin?
3) You can create shortcode in your child theme functions.php https://prnt.sc/1v4taad and show that shortcode on the single product page next to price https://prnt.sc/1v4thib
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