Site is fast, Cart is slow

Hi guys! My site is hosted on Cloudways with Digital Ocean, and loading speed is great, TTFB is great, but every time I add anything to cart it’s very slow (see image https://ibb.co/hdKW51b).
I know, the obvious answer is: “scale the server”, but is there any other way? Like, some mysterious cache thing? Like Redis (don’t much about it)? Or anything else?
I do use a lot of plugins, like Woocommerce Subscriptions, Product Bundles. Is there any plugin that is known to slow Woocommerce?
And it’s all updated to latest versions. PHP is 7.3.
Thanks!