A simple web app written in HTML and JS which shows all charts from an arbitrary spreadsheet. In the ideal scenario, the charts are rendered just like in spreadsheets, so I can see the charts without the necessity to open a spreadsheet manually.
Creating a custom implementation which gets all referenced data seems extremely complicated. Even if I created it on my own, I do not know how to create visualizations in step 5.
What I found and why it is not solution for me? There are similar questions and solutions that use Visualization API to query data from a spreadsheet and the visualize it, such as this answer. Why is this not solution for me? Because my spreadsheets are created by non-tech people who do not follow any good practices, so data cannot be easily queried using Query API. The spreadsheets are a mess. The charts are created by the same folks and they want to customize it by themselves. What I need is to show already existing charts without necessity to make any chart-wise code.