Hello,

Sorry for the delay.

Unfortunately, it is not possible to insert content before and under the product grid. By default, Woocommerce has one category description, and the Basel theme just provides the option to change the location.

We have not tested the reviews plugins we can not guarantee 100% compatibility.

Basel theme has Testimonials element. You can create HTML block: https://xtemos.com/docs-topic/html-blocks/

Insert the Testimonial element in this block and then insert the HTML block into the pre-footer area. You will have awesome testimonials on all pages.

Best Regards