How to reproduce:
1. Create a new 3D URP project
2. In the Player Settings make sure “Show Splash Screen” is disabled
3. In the Build Settings make sure WebGL is selected as the Target Platform
4. Press Build
5. Host build locally (I used XAMPP changing Config → httpd.conf → DocumentRoot and Directory paths to the build path)
6. Open build on the Android device (syntax example for accessing hosted build on a browser “ip:port”)

Expected result: Visible empty scene
Actual result: Scene is dark

Reproducible with: 2022.3.35f1, 6000.0.0f1
Not reproducible with: 2021.3.40f1, 6000.0.8f1
Fixed in: 6000.0.1f1 (fixed version might be incorrect due to the inconsistency reproducing this issue)

Testing environment: Windows 10 Pro
Not reproducible on: Others not tested

Reproducible on these devices:
VLNQA00267, Samsung Galaxy S10+ (SM-G975F), Android 12, CPU: Exynos 9 (9820), GPU: Mali-G76
Redmi 12 (user reported)
Redmi 13C (user reported)
Vivo Y18 (user reported)
Oppo A38 (user reported)

Not reproducible on these devices:
VLNQA00363, Samsung Galaxy Z Fold2 5G (SM-F916B), Android 11, CPU: Snapdragon 865 SM8250, GPU: Adreno (TM) 650
VLNQA00375, Samsung SM-G996U (SM-G996U), Android 11, CPU: Snapdragon 888, GPU: Adreno (TM) 660
VLNQA00321, Xiaomi MI 9 (MI 9), Android 10, CPU: Snapdragon 855 SM8150, GPU: Adreno (TM) 640
Redmi Note 13 (user reported)
Xiaomi 14 (user reported)
Realme 11 (user reported)
Oppo Reno 11 (user reported)
Oppo Pad Air (user reported)
iPhone 13 (user reported)
Galaxy S23 (user reported)
Galaxy A15 (user reported)
Galaxy Tab S9 (user reported)

Notes:

Not reproducible on the Windows Standalone player and in the Game View
Not reproducible on Windows PC (Tested with Chrome browser)
Not reproducible if the Splash Screen is enabled
Issue might be inconsistent so for example instead of entering the URL to the device browser you can create and scan the QR code to open the WebGL Player
Didn’t search for a regressed version since this issue is not consistent there is a very high chance the regressed version I will find will be incorrect
Couldn’t test on iOS due to the errors in the browser, but from the description and provided devices this issue only seems to be reproducible on lower-end and older Android devices