It’s a nice quality-of-life addition, but I don’t know if the game tracks (or if it’s able to track) each user’s system time. The way “Most Active Recruit” currently works for example is it adds all the time you’ve spent on each mission and the waves you’ve passed, but it doesn’t keep track of how long you’ve had the game open, at least I believe that’s the case.
It must be possible, though. Adding this feature should be a matter of adding a line of code to get your system time at quitting. But I’m not IA so I don’t know.
Your English is stellar compared to the things I’ve seen on this forum before. Don’t be self-conscious about it. Besides, find comfort in the fact you took the time to learn a second language, so if anyone ever tells you that your English is trash, usually natives, ask them if they have ever made an effort to learn 2 words in a different language.
Natives have it easy because the main language of the Internet happens to be English, but the majority of them remain monolinguals. Those who are bilingual (or just have common sense) won’t tell you anything, really.