VPN with nth

Hi friends
I have a problem with the VPN connection when I set up the NTH integration
I combined 3 internet lines using the nth method,
but I want to set up a VPN connection for all those connected to the network, but this does not happen.
I add mangle to make routing mark but doesn’t work When I add the VPN route, it connects to the VPN server, but the data traffic is not directed towards the VPN connection.
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