Vulkan requirements for Android
Requires 3D WebView for Android v4.2 or newer, or 3D WebView for Android with Gecko Engine v3.17 or newer.
Unless the application only uses webviews in Native 2D Mode, the target Android devices must support the Vulkan extension VK_ANDROID_external_memory_android_hardware_buffer. This extension is supported on newer devices like Meta Quest but isn't supported on all Android phones that support Vulkan. So, if your application is intended for general Android phones, it's recommended to either only use Native 2D Mode or to use the OpenGL graphics API instead.
Android 8.0 (API level 26) or newer is required for Vulkan.
Unity 2020.2 or newer is required for Vulkan. This is because Unity added support for using Texture2D.CreateExternalTexture() with Vulkan in 2020.2.
Unity 2022.1 or newer is recommended if your project has Multithreaded Rendering enabled in "Android Player Settings" -> "Other Settings", because web rendering may appear jittery when Multithreaded Rendering is enabled with older versions of Unity. Versions of Unity prior to 2022.1 have a bug where Texture2D.UpdateExternalTexture() doesn't work for Vulkan, so 3D WebView must use an alternative approach for updating Vulkan textures with Unity 2020.2 - 2021.3. This alternative approach renders smoothly when Multithreaded Rendering is disabled but can appear jittery when Multithreaded Rendering is enabled. If you're experiencing jitter and are unable to upgrade to Unity 2022.1 or newer, then an alternative is to disable Multithreaded Rendering.