Create filtered Service Bus subscription using .NET Core SDKs

I understood, that Microsoft.Azure.ServiceBus is not able to create ressources

As of version 3.1.0-preview of Microsoft.Azure.ServiceBus you can create entities using ManagementClient without the need in the Microsoft.Azure.Management.ServiceBus library. It has an overload of CreateSubscriptionAsync() that takes in RuleDescription to be created as the default rule. Alternatively, providing no RuleDescription will set up a default rule for you automatically.

There are similar methods available for rules management under SubscriptionClient in Microsoft.Azure.ServiceBus. Look here for samples.