How to Achieve Safari-like Scaling in WKWebView

I am currently developing an iOS app that needs to embed a third-party website. On this website, the best view is achieved in the standard Safari app by pressing the 'Aa' button on the left side of the address bar and setting the zoom to 50%.

I want to replicate this 50% scaling in WKWebView, but I'm not sure how to accomplish it.

I've tried using

webView.pageZoom = 0.5

and setting

webView.scrollView.minimumZoomScale = 0.5  
webView.scrollView.maximumZoomScale = 0.5

but it doesn't display the same way as it does in Safari.

How can I achieve the same scaling effect in WKWebView?