how to add reviews to the grid?

Welcome to our forum.

there are some filter hook for grid items, you can add your own HTML via filter hook

https://pickplugins.com/documentation/post-grid/filter-hooks/filters-post_grid_filter_grid_item_title/

https://pickplugins.com/documentation/post-grid/action-hooks/post_grid_layout_element_id/

you can access to post id by get_the_id() function .

Let me know more help.

Regards