No IPv4 access to RDG. Only IPv6

Okay, got a really weird one here. I reluctantly admit it’s 100% my fault too. On a Server 2019 domain controller with RDGateway installed it’s set up so the business owner can remote in from home to a VM set up on the DC. I also can remote in via the RDG directly to the server itself, so I can perform my monthly maintenance remotely.

A few weeks ago, in the process of figuring out and setting up IPv6 it seems I somehow disabled IPv4 access to the RDG as a way to confirm it was correctly configured for IPv6. Got RDG and all working with IPv6 now. But for the life of me I can’t remember exactly what I did to disable IPv4 to the gateway. I’ve googled quite a bit, and nothing I find seems to re-enable IPv4 on the RDG. Heck, I’m not even sure it’s RDG where the issue is.  I need to re-enable IPv4 so the business owner (and a few other managers) can regain remote access now. Here’s what I’ve checked.

-IPv4 is enabled on the network adaptor.
-IPv4 is enabled on the VM
-Port 443 is not blocked for IPv6 on the firewall
-Checked the policies in Gateway Manager and nothing there indicates IPv4 is blocked.
-Checked the RD-CAP network policy in NPS and nothing there indicates IPv4 is blocked.

I’m at a loss and could use some help in recovering from my own stupidity.