Ovpn files generated by Sophos UTM contain the 'route-delay' option.
However, this option is not supported in OpenVPN core 3.8+, so you cannot import ovpn files unless you manually remove it.
The ovpn download section on the UserPortal mentioned "a compatible third-party OpenVPN client on Windows, MacOS, Linux, or other systems is available, it should also be compatible with the newer versions of OpenVPN".
And the SSL VPN configuration on iOS device, the link to OpenVPN Connect is provided that cannot import ovpn files.
Please provide the ovpn file compatible with the upgraded OpenVPN version.