I have the exact same problem but have no previous setup (6.11.4) to know if it would work, so I'm not sure if its a unraid version thing or just doesn't work. The VPN does work if I ignore my static ip docker - I can get to the router, unraid, unraid bridge/host dockers. I have the route setup on my router for the VPN and unraid gateway. But my whole reason for setting this up is to add the pihole layer for blocking ads and tracking on my phone - which requires being able to access the static ip'd docker.
Something the quick start or the forum doesn't seem to address is the macvlan vs ipvlan, by default unraid uses ipvlan and there have been cases of people using this scenario successfully before 6.11.x on macvlan but not after.