Multi Selection woocommerce filter canvas

Hello,

Following the posts could help you with it.
https://docs.woocommerce.com/document/woocommerce-product-search/widgets/product-filter-attributes/
https://wordpress.stackexchange.com/questions/216070/wp-dropdown-categories-with-multiple-select

and also try to coordinate with the concerned plugin support, they can suggest you some solution for it.