Prestashop is pure eCommerce, woocommerce it's an addon. But both works fine (and free).
Better Prestashop if you have big amount of products, categories, attributes... and of course multiple languages.
Same question here. Tried to update one store (very little one) from 1.7.8.8 to 8.1 and i't didn't work (error updating db).
Basically need to do it for php8, sooner o later I will try again.