I am not familiar with “Cascading”
So I don’t see your WAN IP of 5.205.236.xx anywhere in the log and it looks like it is trying to exit by the openVPN client.
Check the firewall Zones is the only thing I can think of?
________________ Input | Output | Forwarding
wgserver===>wan |Accept | Accept | Accept
wan====>wgserver Accept | Accept | Accept
I am not a 100% on that. My reasoning is everything needs to pass back and fourth between the wgserver and wan.