Home Wifi NAT Type issues

This is due to their upstream network topology... nothing to do with the modem/router.

It was a problem roughly 2 years ago with the Askey modems that had a host of the typical router functions like DMZ, UPnP and Manual port forwarding, DHCP configuration, etc.

As of April 2nd when I went back to a wired ISP to recover full IPv4 functionality again, this had still not been addressed (was still using said Askey, so no... inbound port forwards were still not working, otherwise I would still be subscribing).

If you do a search about it, you will get hits on threads dating back to late 2020, if not further back.

Their choice of XLAT464/CGNAT style approach to handling dual IPv4/v6 stacks causes unsolicited inbound traffic to get filtered/blocked at the outer edges of the network path, well before the packets even make it to your modem.  If it is not first established as an outbound connection, it is not allowed in (ie: must follow a stateful tracking approach, no typical peer-to-peer)

To date, the most viable workaround has basically been to use a VPN... but even that needs some specific configuration for some scenarios because you would need P2P support, as well as a reserved IP for it to work properly (which can ramp up the cost).

You may be able to sort of "trick" a console by going through a standalone router first.  The console will report NAT-2/restricted if the ports are forwarding on that router, but that does not mean the communication will actually flow properly.  P2P style applications may still misbehave because of what is happening upstream in the upper network layers.