Hello,
1/ You need to contact your hosting provider support and ask them to increase memory_limit value.
2/ Follow this active https://xstore.helpscoutdocs.com/article/100-how-to-speed-up-my-website
3/ Disable “Product Variations Swatches for WooCommerce” plugin, and use our variation swatches – https://youtu.be/LgzC4iK-j6A
Do this, then clear all cache and reply back here, please.
Regards