Publishing three sites with SS now, one is 7.0 and two are 7.1 and knowing about Core Web Vitals since last fall, I was told then that it was an experiment and to pay it no mind and all Squarespace ranks poorly on Google crawlers so I wasn't alone.
Now it is no longer a trial and my sites ALL fall in the red, as in 0-49 level, and my urls are poor, still after working tirelessly adjusting images and shortening urls for almost 8 months now.
I think Squarespace Developers can come up with a solution. They usually do, but I want to see them address it and help us with it, outside of forums. This is a concern, even with my 7.1 sites!
So far nothing I have done on the surface of the site from image shrinking to changing url directions, has brought my score up. If anyone has any ideas I'm following!