Hi Laurent,
Unfortunately this cannot be done with the current implementation. Thank you for pointing this out, we will try to add an option for the Reviews order in the next theme version.
A “hack” you could do is the following:
1. Under the PokaTheme Featured Affiliates block (screenshot: https://i.imgur.com/dXB1b2q.png) you can see there is a multi-select with all the Reviews. This follows the order that you see in your Dashboard > Reviews (/wp-admin/edit.php?post_type=affiliates).
2. So if you could modify the order of the Reviews under Dashboard > Reviews, then it would change in the multi-select, too. To do this, you could set newer/older date to your Reviews and go back to the block and choose the Reviews from scratch.
This will be a temporary solution, as I mentioned above we will add this missing feature to our list to provide a fix for this in the next version.
Let us know if you still need help with this one.