Does Vanced really use WebView for playback (the link the article provides suggests it's used for sign-in)?
Aside from forgetting to mention Revanced which is very much alive, I have doubts about the article. It feels like the author realized his headline doesn't work anymore so came up with something plausible sounding...
Vanced and Revanced use(d) a fork of MicroG for sign-in. MicroG is a FOSS implementation of Google Play Services and other Google app APIs but with minimum tracking. It uses the website to sign in, which I imagine is rendered with WebView because the app is so small.
Yeah, I'm running LineageOS with MicroG, so I tried disabling Android System Webview as a test. ReVanced seems perfectly happy to browse/play videos (though I didn't try logging out). The only apps I have that fall over without webview seem to be eBay and Amazon, so no great loss there.