What exactly is serverTimeOffset functionality?

I don't see any explanation anywhere as to what it is used for.

If someone knows and explains it, I appreciate it.

The serverTimeOffset is used to allow you to adjust the time zone displayed when checking a players base with /ao Player command

And what setting can be used ?.

What numbers can be used?

It is that since I do not see any explanation, nor adjustments, nor examples anywhere, that is why my doubt.

Is it necessary to change it or is it left as is?

It's an int value for time offset to est you can ignore if you don't want to change it. If you can control your server time this is not needed but if your on a host and want to display a different time to users adjust buy x hours with that value

Many thanks. Very friendly.