Do you support JavaScript? I always got the impression that that’s one of the most resource-heavy parts of the modern web, but at the same time it’s hard to render many modern webpages (webapps?) without it..
I hope you add https://codesandbox.io/ to the list of websites that you aim to explicitly support! They use VS Code's editor (Monaco) internally, which does not work in WKWebView on macOS.