ErnestThornhill
I didn't install any client on the phone, it's Android's built-in IKEv2/IPSec PSK support.
I will not use VPN at the same time on two profiles, one by one, and each has its own configuration.
The DNS that the phone receives from Wi-Fi, not from VPN, is used. This is the DNS address of the provider.
With these settings, the main profile works fine and connects to the vpn server with "Always-on VPN" enabled, while the second profile can only work when this feature is disabled, otherwise the vpn doesn't even try to connect.