This was such a random post on HN, because I didn't even know about echarts about 2 weeks ago. I had been using amcharts for the workout analysis in XRWorkout for several years but wanted to switch to a more open library.
Converting the old amcharts code to echarts worked almost automatically with Gemini 2.5 Pro and since a bit over a week all stats in the game ( via webview ) and in the web on the user portal are now using echarts.