Connection Turris Shield between modem and router?


I have purchased the Turris Shield.
Before I get started, I have a few questions:
My internet connection is currently working as follows:
Provider<->Draytek Vigor 165(modem)<->Fritzbox7590(router)<->LAN/WLAN. If I understand various connection plans correctly, the Turris Shield should sit in front of the router. Can I place the Turris Shield between modem and router? Since I need port forwarding in the router and the Turris Shield apparently has a router function, there could certainly be problems? Port forwarding is probably not possible in the Turris Shield, apart from the double NAT. Do you see a functioning possibility of a meaningful connection?

Best regards…