Nice use of Chart.js! If you run into performance limits with v2, I would recommend trying out v3 (we're close to a 2nd alpha release) as it has a lot better performance.
Docs on the latest dev code: https://www.chartjs.org/docs/master/
Docs on the latest dev code: https://www.chartjs.org/docs/master/
It should also be possible to render the chart in a WebWorker via the OffscreenCanvas API.
To be honest though, the data should be decimated before being sent to the chart. Some notes on it https://www.chartjs.org/docs/master/general/performance#data...