That page inherits the shop page layout in general in combination with WC Marketplace plugin styles https://wordpress.org/plugins/dc-woocommerce-multi-vendor/ What exactly do you want to change there? Could you explain in more detail?
Your page size is very large because of the images that you use https://prnt.sc/10sckjh So, optimize image and try to reduce the page size to 2Mb at least. You can try https://tinypng.com/ service. Also, don’t use png images if your image does not require transparent bg because it’s much larger than jpg, for example compare results of one of the logos that you have https://prnt.sc/10scogq or slide image https://prnt.sc/10sct0b
