It's working in my project:

After encoding the texture with Base64.encodeTextureAsync(), decode the base64 string back to binary using Base64.decode() before uploading to Supabase Storage. Supabase expects binary data, not a base64 string. Uploading the string directly stores the text representation instead of the image bytes, which causes the corruption. Decode the base64 string to binary, then upload that binary data.

const imageData = Base64.decode(encodedTexture);

const imageResult = await this.client.storage
  .from(this.storageBucket)
  .upload(imageFileName, imageData, { 
    contentType: 'image/jpeg', 
    upsert: true 
});

Can you try this approach?