Ask HN: Is server side rendering necessary for good SEO of a React app on Google

In my company we are working to release a new version of our website which heavily uses React. For SEO reasons, we have been asked to create server side rendering. Historically, search engine crawlers do not support JavaScript. However, I have read a few blogs that hint Google renders javascript.

Is there any proof/does anyone have any experience with Google improved search rankings with server side rendering?