Thank you for the files and explanation.
I have noticed that there are three VPN instances configured on the device, all associated with the 192.168.255.0/24 network. As a result, there is only one route in the routing table with one of the tunnels, and the device uses that tunnel to route traffic for the mentioned network.
Could you please remove or disable the other VPN instances and keep only the one you are actively using? After making this change, you may want to restart the device. Once the device is up and running, please test the ping response time and let me know the results.