+1 for this.

Here's an example, Trying to show Google Ad Spend vs Revenue.

Here we've been able to succesfully do this in Oviond. But It comes out confusing with Agency Analytics by not being able to have both metrics on the same line

To elaborate further on this, currently when comparing 2 metrics [Y] (with the same output value eg. a dollar value) across a single dimension [X], instead of the metrics displaying comparably to each other on the Y-axis, the second metric is measured against a second Y-axis split at different intervals to the first Y-axis, meaning the visual comparison of the data at each X-axis is not reflective of the actual values.

A simple use case for this is comparing spend (cost) and revenue (conversion value) from a Google Ads campaign on a bar chart, month by month (looking at the past 12 months). At a quick glance we should be able to see stability or fluctuations that need to be explained. Currently, most of my cost bars look higher (or the same level as) the conversion value bar even though the conversion value is twice the amount of the cost (see screenshot for current experience).