How to make the traffic of a L2TP user access the Internet locally?

For Windows, you can refer to this configuration:
How to uncheck “use default gateway on remote network” on the computer？

For iPhone you can click the following path:
Settings > General > VPN & Device Management > VPN > Add VPN Configuration, then choose VPN type to L2TP


If this is not disabled on iPhone, it can access other network segments under the VPN, but traffic will access the internet via VPN.
If it is disabled on iPhone, it can only access users with the same tunnel address, but traffic will access the internet via local.
As for other brands phones, you can check if they have the same features. If yes, it can support the traffic of a VPN user access the Internet locally. If not, it can't be supported. This is the performance limit of the phone.