Unable to get WebGL GPU support in GCP CloudRun container using Playwright/Chromium

I'm trying to deploy a container to Google CloudRun which lets me use WebGL which is GPU hardware-accelerated.

I have the following front-end code (using node) to initialize WebGL and query its vendor and device:

        console.log("Checking WEBGL capabilities...")
        const canvas = document.createElement("canvas")
        const gl = canvas.getContext("webgl")
        if (gl) {
            const debugInfo = gl.getExtension("WEBGL_debug_renderer_info")
            if (debugInfo) {
                const vendor = gl.getParameter(debugInfo.UNMASKED_VENDOR_WEBGL)
                const renderer = gl.getParameter(debugInfo.UNMASKED_RENDERER_WEBGL)
                console.log("WEBGL Vendor:", vendor)
                console.log("WEBGL Renderer:", renderer)
            } else {
                console.log("WEBGL_debug_renderer_info not available")
            }
        } else {
            console.log("WebGL not available")
        }

The node program is executed using Playwright(1.52.0)/Chromium like so:

    const browser = await playwright.chromium.launch({
        timeout: timeoutInSeconds * 1_000,
        logger: {
            isEnabled: () => true,
            log: (name, _severity, message) => api.logger.debug(`${name} ${message}`),
        },
        headless: true,
        channel: "chromium",
        args: [
            //"--use-gl=egl",
            "--use-gl=angle",
            "--use-angle=gl-egl",
            //"--use-angle=gl",
            "--ignore-gpu-blocklist",
            //"--use-gl=angle",
            "--no-sandbox",
            "--headless=new",
            "--enable-gpu",
            "--enable-webgl",

            // "--use-angle=vulkan",
            // "--enable-features=Vulkan",
            // "--disable-vulkan-surface",
            // "--enable-unsafe-webgpu",
        ],
    })
    const page = await browser.newPage({permissions: ["storage-access"], viewport: {width: 40, height: 40}})
    await page.goto(url, {timeout: timeoutInSeconds * 1_000})

The docker base image for the container uses mcr.microsoft.com/playwright:v1.52.0-jammy.

As you can see I have tried many different combinations of flags when spawning Chromium (as trying different "solutions" I found on the web) but never did I see NVIDIA to be used, but always

WEBGL Vendor: Google Inc. (Mesa)
WEBGL Renderer: ANGLE (Mesa, llvmpipe (LLVM 15.0.7 256 bits), OpenGL 4.5)

or

WEBGL Vendor: Google Inc. (Google)
WEBGL Renderer: ANGLE (Google, Vulkan 1.3.0 (SwiftShader Device (Subzero) (0x0000C0DE)), SwiftShader driver)

depending on the flag-combination, suggesting software-rendering only.

I made sure the container sees the NVIDIA GPU and proper drivers are installed by running nvidia-smi inside the container resulting in this:

| NVIDIA-SMI 535.216.03             Driver Version: 535.216.03   CUDA Version: 12.2     |
|-----------------------------------------+----------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |         Memory-Usage | GPU-Util  Compute M. |
|                                         |                      |               MIG M. |
|=========================================+======================+======================|
|   0  NVIDIA L4                      Off | 00000000:00:07.0 Off |                    0 |
| N/A   75C    P0              N/A /  72W |      0MiB / 23034MiB |      0%      Default |
|                                         |                      |                  N/A |
+-----------------------------------------+----------------------+----------------------+
                                                                                         
+---------------------------------------------------------------------------------------+
| Processes:                                                                            |
|  GPU   GI   CI        PID   Type   Process name                            GPU Memory |
|        ID   ID                                                             Usage      |
|=======================================================================================|
|  No running processes found                                                           |
+---------------------------------------------------------------------------------------+

which suggests GPU and driver being available.

I'm really running out of ideas what else I could try. Does anybody have any further ideas what else to test or which combination of flags actually works ?