Port forwarding does not work (GL-MT6000)

I have a GL-MT6000 in repeater mode and my Nas is connected via LAN (2.5gb port). I have setup port forwarding to the NAS ip address and Mac address for the port 443. This setup was working with a repeater from a different brand. But using the GL-MT6000 this does not work.
I also tried to use the GL-MT6000 in router mode and setup the port forwarding from my main router to the GL-MT6000 and from there to the NAS and this does not work either. Any idea what is going wrong?

If you don't want to have the MT6000 acting like a router, go with Extender/WDS Mode instead. This will mostly disable all NAT features.

I have it in Extender mode right now. But the port forwarding still does not work.

I think I found the issue... it is not possible to setup both WAN interfaces as LAN interfaces and use them both. It would have been super nice if it would be possible to use both 2.5 gb interfaces but this does not seem to be possible with port forwarding. Everything else worked without any issues.

I don't know if this is a hardware limitation or a software bug or if there is a work around. But my workaround is to have my computer in the Wan 2.5 gb port and the NAS in the Wan/Lan port. Like this port forwarding works for the NAS and I can enjoy 2.5 gb transfer speeds between the NAS and my computer.

Defnitions are different with different brands. Repeater or extender in one brand is something totally different in another brand. (some implement pseudobridge, some implement proxy-arp , some use the name repeater as Network Mode name)

The basics are Layer2 (bridge) or Layer3 (router). Router may or may not include NAT (SourceNAT or Masquerade). Pure bridge (L2) does not act on or change Layer 3 (=IP addresses)

But not everything is pure .. in wifi connections often a L2.5 Pseudo-bridge is used. This uses MAT (MAC address translation), IP of client with MAC of repeater interface.

Port forwarding and DMZ host use Destination NAT on Layer3. Needed to initiate a connection through the firewall from WAN to LAN.

AFAIK with GL.inet GUI the network mode router/extender/bridge are ...

Router : is L3 router with SNAT from LAN zone to WAN zone. NAT cannot be disabled in the GUI AFAIK.
Extender : difficult one, because not documented, I assume L2.5 pseudobridge for wifi connection always uses the MAC address of the repeater, clients have different IP addresses
Bridge: only for devices without wifi interfaces, or when ethernet or WDS is used.

Bridge can clearly be seen in LUCI, combining some interfaces, like the LAN interfaces.

With "DMZ host" you forward all incoming WAN ports on the WAN IP to one LAN client on its LAN IP. The GUI allows for one DMZ host
With "Port forwarding" you forward the incoming WAN port to one specific LAN client IP and port. The GUI allows Port Forwarding from LAN to WAN also.