Nighthawk M1 (MR1100EUS) DMZ not working on latest firmware

Dear Netgear Support and others trying to help :-)

I am running the MR1100 with a public ipv4 address associated to a dyndns record but DMZ enabled does not allow any access on any service hosted behind the MR1100. When enabling a single port in port forwarding (e.g. port tcp 22) then I can access that 1 service from external but this is not the intention when using a DMZ.

I have already reset the device once using the webui but might wanna do it again using the hardware button.

Any other ideas?

And please note that I am IT professional so do not botehr me with the usual "Hav you tried to turn it off and on again" replies.
Thanks so much

Thomas