Fix WooCommerce API & Cart Widget

I’m looking for a quick but thorough check-up on my WooCommerce installation. WordPress is flagging the “legacy” REST API as deprecated. And Woo settings says it is in use. And there is Printful connection in this site, which is the only API used. Another thing is, the shopping-cart widget on the side has gone mad. First it did not open at all, once i cleared the cache it was blank. The store runs on LiteSpeed Cache, so any work needs to play nicely with its optimisation rules.