Well, I prefer not to put a “\n” in dates but you do you mate

int time = 1686650138000;

I accidentally the timezone.

All other formats are inferior

In ISO8601 I trust.

POSIX time or bust!

As someone that works a lot with high-frequency sensor data, we need the microseconds too!! Use this one: %Y-%m-%d_%H:%M:%S.%f

This is the way.