You are in a difficult position as an app developer.
- You are "Mr. In Between", bouncing between
- Your guru, the sponsor with no idea about data visualization
- this board, with pre-cooked solutions for other problems, and
- your lack of study of the fundamentals to collect and display data.
I am reminded of the advice in the 1944 song "Accentuate the Positive"...
https://www.google.com/search?q=accentuate+the+positive+lyrics
Note the references in the song to "Mr. In Between".