In principle: An architecture is recommended in which the device in which the SIM card is installed establishes a connection to a server and transmits data there. Making devices accessible via the free Internet involves security risks such as botnets and enables attacks.
DynDNS: Technically possible, but not recommended for security reasons. Unfortunately we are not allowed to offer technical support and advice here.
VPN (Device to Server): A VPN connection can be set up with some router manufacturers. The security is appropriate with correct setup. Since the setup is strongly dependent on device manufacturer and software, we unfortunately cannot offer any technical support.
VPN (APN to Server): This is a product of our network provider: All devices are running in a subnet with reachable static private IPs. The service is subject to a charge and is worthwhile for a larger number of SIM cards. Please contact us for a non-binding offer.