I thought I would try to use offline installer but quickly realized that one has not been updated for over a month according to the title. So no reason going that route.
You are referring to the FORUM POST, that doesn't automatically mean the Offline installer ITSELF hasn't been updated, because in fact it has.
The problem is likely your local cloudflare node that hasn't been updated with the latest version. We don't have any version other than 3.7.1 on our server, but nobody connects to our server directly, you all connect to your local cloudflare node, and of course every time there's an update, we use the SAME (single) API call to communicate cloudflare with a list of updated files, so their nodes would know they must refresh their version.
Most nodes do this in seconds, some in hours, some might be stuck for days. There's no way for us to know that, it's completely outside our control and you can verify this is the case, if you use a VPN, so you would connect to a different node, showing the problem has never been GSX, the FSDT Installer or the FSDT server, it was JUST a cloudlfare network replication delay.