Hi there, "ML" from France.  When I worked in the Boston area, several years ago, the more significant data centers were outside of Boston.  I'm thinking of the Equinix locations in Billerica and Waltham.  From a simple Google search, it looks like there are more options than I remember.

Ultimately, we went with ColoSpace - https://www.firstlight.net/colospace-is-now-firstlight/.  They've recently been acquired by FirstLight.  The interesting thing about ColoSpace is that they lease several rows within the larger data center, and then will provide their customer with individual cabinet space.  So, you could essentially have infrastructure in multiple locations, if you need it, and yet have one vendor to deal with.

All the best with that project.  Boston is a great town, and September is one of the more pleasant times to be there.