miniupnpd not working with upstream router/ modem with public IP

Miniupnpd is not working with my providers upstream router with a public ip address range.
if I put in my config my private ip address into my external ip upnp fails to start.
if I leave it to detect its own external ip it says it is a public address and upnp is not possible.
if I use stun to get an external interface it says i have a nat issue:

STUN: ext interface wan with private IP address 192.168.0.142 is now behind restrictive or symmetric NAT with public IP address 115.189.82.94 which does not support port forwarding NAT on upstream router blocks incoming connections set by miniupnpd Turn off NAT on upstream router or change it to full-cone NAT 1:1 type

There is no nat on my upstream router it is using dmz to forward all ports to my router.
I do have an upstream CGnat but if a port is requested it dynamically opens when requested from the client and mapped to an upstream port so I'm told.
It seems to work with my providers router, and works with my xbox with out issue connected directly to my providers router.
my provider requires me to use their router (tag locked sim card)

Start by reproducing the miniupnpd configuration with the provider router, DMZ forwarding, and the reported upstream CGNAT setup. Compare behavior when using the private address, automatic external-address detection, and STUN. Done means the cause is identified and a concrete configuration or code change is specified, with the port-forwarding behavior verified.