Trend visualizations should be used for datasets that have a sequential, numeric X that is not time.

Trend assumes that you are not using a timescale (or at least not linked to the time range you select in the dashboard), otherwise you would use a time series panel. Example: horsepower per rpm.

Zoom-in like you described is to change the time range ("I am seeing a month, I want to see a specific week" -> instead of manually choosing it in the time picker, select range on graph). The trend panel doesn't implement this behaviour as it's not using the time range.

I do see a case of setting a min-max X in Trend with it. I do encourage you to evaluate if doable and propose a Pull Request on the source code.