I apologize for the late response, I don't seem to get emails when there is a reply. I've got to look into it....
Anyway. So yeah, turning JS off worked, so that led me to dig into what was happening there, and I think I pinned it down.
They use a service called Sailthru for the newsletter signup, and NextDNS blocks that. I believe that the JS they use to load that probably hangs when the request to get Sailthru JS never completes. When I disable NextDNS and use my ISP dns the page loads fine.
Really odd that it woks fine in Safari.
But now an answer if others have a similar sittuation.
