To begin with, according to your last point, your router might not have Public IP address. if this is the case, this means that you will not be able to establish VPN connection to the router. In such case, you would need to contact your ISP and ask for "Public IP" service. We have brief article about public IP address, in which you might be interested. You can find ir here.
From the picture, which you uploaded, I can see that your router's configuration is incorrect: "Remote tunnel endpoint IP" field cannot be "172.16.1.0", since this is networks address and not host's. Simply solution: change IP address to "172.16.1.2".
Regarding your mobile phones configuration: CA certification should not be needed in "Static key" connection. It might indeed be a possibility that your phone is trying to establish TLS connection instead of static key.
In this case, personally, I would not recommend to start working with OpenVPN with mobile phones, since that might lead to frustation, because in the beginning you have too many unisolated variables and each of them might prevent connection from being established. Best practice would be to create your first OpenVPN tunnel from any computer (running OpenVPN GUI application) since it will allow you to more easily change settings and troubleshoot the connection/check detailed connection logs. And once the connection from computer will be working, you would be able to transfer all same configuration to mobile phone and troubleshoot only its variables, leaving all Public IP/connection/OpenVPN uncertainties aside.