That’s not a webview, it’s a separate api with fewer abilities. Custom tabs I believe.
You can see for example that it always opens as a fullscreen overlay in your app and that it always has that bottom or in your case top bar.

yes, zen4 is the ryzen 7xxx ans onwards. I think they will change the naming scheme again after the 9xxxs now though.

In my case my 5xxx cpu shows avx2 (256bit) in /proc/cpuinfo, I assume you will find avx512 there if you have it.

Also apparently there are mobile and server cpus with 7xxx names that are zen3. It is a mess certainly.

Affected CPUs: AVX-512 capable CPUs. Intel Xeon, Zen 4 AMD Ryzen and EPYC and up.
Affected function: UYVY to YUV422 format conversion (pixel-level color encoding).
Speedup: 18/10.98 = 1.64x (Since all AVX512 cpus should support and previously have used avx2(56)).

Apparently as part of an ongoing series of rewrites, they made a color encoding conversion function run 64% faster on server CPUs and somewhat recent AMD CPUs