It's been suggested (answer and comments by Ryan M) that this question is on-topic for this site. I'm not so certain but willing to risk having my knuckles rapped.
I've come to the point where I need my Squarespace website to do more than the Squarespace platform is designed to do, namely provide server-side access to Node js and Ajax. Squarespace permits no server-side access whatsoever even from within its "Developer Platform."
The critical page on the site retrieves data stored on the AWS DynamoDB servers and dynamically populates a table on the page. I need secure, credentialed access to the servers, thus requiring server-side Node js and Ajax functionality. I need a site-builder because I'm not competent to build one and my non-profit group hasn't the money to hire a professional. Those twin requisites constrain the set of appropriate site hosts.
It seems that I need to migrate the site to some other website-building platform similar to Squarespace but that allows server-side access.
I would like recommendations for quality website-building platforms similar to Squarespace but that provide server-side access to Node js and Ajax functionality.
I would like to solicit recommendations from knowledgeable people for three to five sights ranked from most to least preferred with reasons.
I would also like to know if you believe that more information about my site and its requirements is needed for a reader to respond effectively.