No Connection to anything when connected to Wireguard from internal network

[Roooker]

Hi,

i am having trouble solving a problem with my Wireguard configuration.
First let me give a bit of background.

My hard wired setup:
Internet -> DLS Router -> OPNsense
x.x.x.x -> 172.16.0.1 -> 172.16.0.2 on WAN port
Internal LAN 10.1.1.1

The DLS Router forwards port 51820 to the opnsense. (I also tried exposed host)
OPNsense configured via road warrior guide from the official docs.
Everything works flawless as long as the client is on an external network.
As soon as i try to connect to VPN from inside the network.  I get no response from the server back.
The URL in the VPN Config points to my public IP attached to the DSL Router.

I have checked all FW Rules and there seems no issue. I was able to connect to VPN from the internal network when setting a entry in /etc/hosts on the client which points to internal IP of the FW (10.1.1.1).

However, i would like to remain connected to VPN even when leaving my home network, therefore this is not a final solution.

I suspect this to be an issue with the Double NAT, however i am unable to pinpoint or resolve it.
I already tried setting a custom route in the DLS router, which points 10.0.0.0/8 to 172.16.0.2.

Any idea on how to proceed? I ran out of ideas....