The current solution for last execution data is not ideal. It requires too much setup with addtional nodes and does not work during development of a workflow.
Maybe this should be a seperate node, or maybe the lastExecution of a workflow should at least be saved to global state by default.
The current plan to make that simpler in this case and many others is to create a kind of ProcessOnce-Node (will probably not be the name).
So users would simply send in the items, define a unique property which can be used to easily check if something got already processed (like ID or timestamp and that would be it. Items which would got processed by the workflow before would pass and all others would be removed.
Sadly not, our team is still very small and we are currently trying our best to find the perfect developers to join us to be able to release new features faster.