WooCommerce keeps products in WordPress's own tables: a product is a post, a variation is a child post, and prices, stock and SKU sit in post meta. Attributes that shoppers filter by are usually taxonomy terms. That shape makes it easy to extend, and also means imported data has to be written through WooCommerce's own CRUD layer or REST API, not directly into tables, or lookup data and caches fall out of step.
Orders are different. High-Performance Order Storage, stable since WooCommerce 8.2 in October 2023, moves them out of posts into four tables: orders, order addresses, order operational data and order meta. It is on by default for new installs, and existing stores have to enable it. A migration into a new install should target HPOS from the start. Any plugin that reads orders from post meta needs replacing or updating before launch.