Question about FRITZ! FRITZ!Box 5590 Fiber

No, it definitely does NOT work, I bought the expensive AVM module separately and installed it without success.
I have installed the Zyxel module in the Fritzbox, but it does not work.
I have tried the option from AVM to write the original MAC address of the Zyxel module to the AVM module. Does not work.

I have written to yallo x times and get no response.

If you haven't bought the FB yet, I would advise against it.

I still use the Fritzbox by setting the DMZ in the Zyxel box to the IP address of the Fritzbox.

Among other things, the Zyxel does not support VPN