IPFire behind FritzBox 7490 - need to see IPs unmasked


i am new to IPFire - and in Firewalls in general. But by reading in the forum - i was able to build this setup (works fine).

All works fine - PI-Hole is doing the job also.

Only one main issue: i want to see the host ip from the IPFire subnet - within the net of the 7490.
Reason: so i could create time amount restrictions for my kids (IPFire does only provie a time period for internet usage - but not a defined amount of time within this period).

So i want to “unhide” the host IP of the devices behind IPFire (GREEN).

NAT is enabled for GREEN.
Tried to disable NAT (IPFIre WebGUI --> Firewall options --> Masquerading/NAT). Then i still could reach the devices within the FritzBox net ( - but was not able to access to internet.
The FritzBox is configured for use static routes:
Net: (GREEN)
Gateway: (IPFire external ip within net of FritzBox)

I have no special ruled defined regarding NAT. No idea how to get the ips numasked to the fritzbox net. Or how to solve it otherwise.

I you can - please give me a tip what could be done to solve this main issue.

The reason that you now cannot connect to the internet is not IPFire it is the Fritzbox that simply not route 192.168.100.x to the internet if it is configured to 192.168.178.x