You can’t change the System WebView unless you use root or an alternative Android distro that allows you to change it, like Iodé does.
The Android System WebView by Google is hardcoded into an internal list as one of the very few allowed ones.
https://www.androidauthority.com/what-is-android-system-webview-3267814/



They also spoke against the denial of the volunteer Chat Control in the EU and said they will do it anyway (likely illegal).