[Chartjs]-I can't work out how to tree shake chartjs with vue3

as stated in the docs here you need to import and register all the elements you are using:

import {Chart, DoughnutController, ArcElement} from 'chart.js';

Chart.register(DoughnutController, ArcElement)

Instead of importing the DoughnutController and ArcElement you need to import and register the elements you are using.