I’m struggling to follow your second result screenshot - can you cleanup your variables (link) and give them meaningful names?
Variable-naming and cleanup discipline is paramount for a developer.
The Java code was easier to follow - your flag is 0, so it means that 10 is not a prime number.
Check if you’re populating the “message” field in all the debugLog steps.
P.S - It looks like you replicated the code without understanding what it is doing (particularly the logic under Repeat). Use the “debug” functionality on Designer, to follow the variables and the flow.
KM