I couldn't find any thread in the community about generating a Mekko charts just using GSheets.
Does anyone how we can do that?
Here's how to do it in Excel: https://www.mekkographics.com/how-to-create-a-marimekko-chart-in-excel/
I have figured out how to almost get there with some data processing. For example, let's review the GDP by country and source, to visualize its distribution. I was able to get the Mekko chart, but I'm missing the countries in the X axis.
Here's the data and spreadsheet: https://docs.google.com/spreadsheets/d/1xVFf8_pbVj45W39qDs7MY5cLE_zf1YlJcSzvqWfazg8/edit#gid=1149840583&range=V1
Putting the names across the bottom isn't possible in this way, you will either have to do it manually with text boxes or use a chart subtitle to identify each column.
There is a great tutorial on how to set up Marimekko charts in Google Sheets here which details how these charts can be made, though the takeaway here is that there isn't a direct way to add axis-labels using the chart itself.
In this case, I would suggest that you let Google know that this is a feature that is important for Google Sheets and give them the idea to have it implemented.
From the Google Sheet UI (from the page in which you can see an open Spreadsheet), follow the Help > Help Sheets improve
menu item and detail in the following Send feedback
modal the information for this request.
Google's Issue Tracker also exists as a place for developers to report issues and make feature requests for their development services, though as this is normally for developer tools such as Apps Script or APIs, the best course of action would be the aforementioned Send feedback
option from the UI.
There is however an already similar feature request on Issue Tracker asking for the inclusion of Mekko charts in Data Studio - this request can be found here.