Hi Frederic,
I recently experienced the same problem regarding the loading times of the page that holds a lot of anychart widgets. I fixed it by using the dataviewloader widget for the bigger charts. The result is that the page will load and all parts from the dataviewloader will load after the page is loaded. You can style a spinner to show the progress.
Inside the widget you can set ‘visibility handling’ to true which results in the chart only being loaded when the tab is opened (when using a tabcontainer).
GL! Ruud