Hello,
1, 5/ Theme options > WooCommerce > Shop > Products style > Show Variations As Simple Products > Off.
2/ Please read this article – https://xstore.helpscoutdocs.com/article/100-how-to-speed-up-my-website
Reduce initial server response time– contact your hosting provider, because it is server-side; https://prnt.sc/qNw5rOWjzqkl – https://kinsta.com/blog/make-fewer-http-requests/ https://wpengine.com/resources/how-to-enable-gzip-compression-for-wordpress/ https://wpastra.com/add-expires-headers/ https://www.keycdn.com/support/reduce-dns-lookups https://authoritywebsiteincome.com/4-ways-to-use-cookie-free-domains/
3/ How does placing order email work when the default WC theme – Storefront is activated on your site?
4/ Single product builder > tabs https://prnt.sc/Xzc0LvAXbkPM
Regards