Review Plugin for Squarespace Site

I manage the above lifestyle account and want to add an end-user review page.  I purchased a commercial hosting package as well.   Our site does not fit into the Squarespace Commerce model; clients want to remain confidential but let site visitors know their opinions. 

The client chose Squarespace, and WordPress hosts the rest of my managed accounts. On my WordPress sites, it is simple to add a third-party plugin that allows users to post reviews for admin approval.  Once approved, they appear on the review page.

I am struggling to find a similar third-party solution for the Squarespace account that works directly on the site without involving Google reviews.

I need some suggestions, please.