updating an operation status to EXECUTING/SUCCESSFUL/FAILED is covered by the inbuilt Smart Rest 2 templates - is there a specific reason to add it to your SR templates?
You can find the in-built templates here. To update an operation to EXECUTING you would send 501,<<your operation type>> to topic s/us
yes, because only one uplink topic can be configured for the gateway, we have used smartRest2.0 templates to upload measurements in one command. We can’t use static topic s/us for another uplink topic.
This limitation increases the complexity of your device integration very much. You will have to cover all the simplifications that are usually covered with static templates by creating many custom templates. You will also discover that certain essential features for a production level device integration (like software management) will become impossible. If you must choose between custom and static templates I’d rather use only static templates.