Textures and materials not loading in iOS (iPhone & iPad)

Dear everyone,
I have issue with loading textures and materials in iOS (iPhone & iPad). but It obsoletely works with Android, Windows and Mac browsers.

Step 1:
I did compression for all the textures using Basis - App crashes sometime. Textures & materials not loading

Step 2:
I didn’t compression for all the textures - Now It loads what I expect (output) but not at all times. It crashes many times.
Profiler Details:
Drawcalls : 246
VRAM : Total - 486

I am using physical shading material for the asset. Can I use this shading material and It supports for all the platform especially iOS.

Thanks in advance.

The drawcalls and VRAM usage looks high.

Does the page crash on iOS? Do you get any useful console logs when looking at at devtools via Safari?

Can you share a build of the project, both with Basis and without please?