Fortunately MacOS users upgrade very quickly. High Serria which is slowly waning at 7% came out in 2017. Compared to windows where twice as many (16%) at still using Windows 7 and won't be able to download the Webview2 update which Microsoft kindly provides.
https://gs.statcounter.com/windows-version-market-share/desk...
https://gs.statcounter.com/os-version-market-share/macos/des...
Really depends on your market I guess and how much legacy webview browser support you need.
Or really how much you'd need to add polyfills like `@babel/preset-env` to keep the JS equal.