Stacked Area Chart: Negative and Positive values not oriented at 0

Hello!

I have a stacked area chart with positive and negative values. I would like both of their "baselines" to be zero.

However, this is not the case:

Whenever there are both positive and negative values, the bottom line gets "pulled up" to meet the top of the top lines. The values between 2020 and 2021 are around -50 to -55 but here they're showing up around the 40 mark.

I understand why this might happen, but for my purposes I'd like it all to be at zero.

I found I could achieve this using lines on the stacked bar/column chart, but this requires a different column for each line which for my purposes is tedious:

I know this can be displayed as a stacked bar chart itself, but I prefer the line visual.

Does anyone have advice about how to fix this? How difficult is it to create a custom visual from an existing one?

Thanks in advance!