I have created a bubble chart following sample at https://github.com/OfficeDev/office-js-snippets/blob/main/samples/excel/10-chart/chart-bubble-chart.yaml
I would like to know how to set via api. A code snippet would be helpful.
You could refer to Excel Add-ins with Chart to get some information, and Chart APIs details are in Excel Chart APIs page, you could refer to Axis and Series sections.
I have added a function changechartproperties base on your snippet: https://gist.github.com/donlvMSFT/3169ad1cb17bde3b04a35f19125a87eb, wish could help.