When we had to do similar things, we found that it was much much much faster to take all that sort of stuff out of the DOM and put it into Canvas. You can still wrap React around it for the UI and controls and data passing and all that, but the actual rendering need not involve the VDOM or even the real DOM at all. With ChartJS we were able to get it to show tens of thousands of individual data points in a time-series scatterplot, each datapoint interactive and real-time, with no noticeable lag. And it was super easy to integrate into our React app. https://www.chartjs.org/
If it's not just charts, here's another canvas-based drawing lib: https://konvajs.org/docs/sandbox/20000_Nodes.html (and its React tie-in: https://konvajs.org/docs/react/Intro.html)
Not trying to discourage you from exploring Svelte if you want to, but it might be less work to just use an existing optimized drawing lib. Regardless of the JS framework used, the DOM is going to be much slower than a Canvas.