It's been a week since I set my site's CNAME and it has not propagated

A week ago I set the CNAME on my domain. On every other host service that I've worked with this change would have been propagated globally within a few hours, perhaps a day or two at most. 

With SquareSpace, I've been waiting a week and nothing has happened. I've emailed 'customer service' multiple times, and no response. Chat is also completely unavailable.

I cannot launch my site (which is hosted on Google Firebase) until this record has been propagated so that Google can verify that the domain is mine. This totally unacceptable. 

Is anyone from SquareSpace paying any attention at all to these forums? 

Is anyone from SquareSpace going to reply to this? 

Have you followed these steps?

Connect custom domain to Firebase.

Those instructions are out of date.

I returned to Google's Domain setup instructions and they seem to have changed, now requiring only TXT records rather than a CNAME record. Once I added the TXT record it propagated within a few minutes and I was able to verify and activate the domain. It seems like TXT records are being propagated but CNAME records are not.