UTunnel has client application for Windows, macOS, iOS and Android platforms (we are working on one for Ubuntu and it will be released soon). It also allows you to configure manual VPN with native OepnVPN client or on your routers.
Popular Support Articles
How to Fix VCRUNTIME140dll is Missing Error while launching UTunnel VPN on Windows device
Connect with native OpenVPN client on Android
Install UTunnel VPN on Android device