Hi @Orange256,
Retry strategies concept is related to incident management which is handled by camunda. (In case of service task failure, configured retry strategy to be used and incident to be created once all automatic retries get consumed.)
No need to throw BPMN Error. BPMN Errors can be used in case of business errors or handling errors via the process.
I believe that what we have here is considered as technical error and can be handled directly by camunda.
https://camunda.com/best-practices/operating-camunda/#modeling-for-easier-operations
so in short, remove BPMN Error logic from your model. And since you need the whole called process to get recalled in case of service tasks’ failure then tick async before for the call activity only (not for service tasks)