The debugger gives an estimate, it is close, but not necessarily the correct amount of resources your game uses. Most often than not, the problem is CPU usage.
The best way to test is export your game with Node (as NW.js if available on free version), run the game and monitor the CPU and RAM usage via Task Manager (on Windows). If you're developing for mobile you should test on that as well. Pretty much export and test on the actual device you're developing for.
In general most modern tech have at least 1GHz CPU (I doubt C2 games utilize multiple cores) and 4GB of memory you might want to aim quite lower than that to make sure it runs great on any device.