Squarespace doesn’t provide any embedded SSO integration
If you really wish to integrate any IDP to Single Sign-On (SSO) with Squarespace then you don’t need to have dev knowledge because a solution can be achieved with an easy setup.
Here’s the link to steps that you can add on Squarespace’s end to retrieve values from JWT which will help the users to login into their Squarespace account seamlessly using Single Sign-On
