I'm having the same problem, but with framework nextjs. It is not copying a crucial directory called _next with my embedded website exported.

I don't know why, but I tried many options on build.gradle inside android block, like aaptOptions, androidResource, both inside defaultConfig, inside buildTypes.release, any of it worked.

I found a solution for this reading the AAPT source code (here) it defines the ignore assets pattern like this:

const char * const gDefaultIgnoreAssets =
    "!.svn:!.git:!.ds_store:!*.scc:.*:<dir>_*:!CVS:!thumbs.db:!picasa.ini:!*~";

Also in this source code, it reads the env var ANDROID_AAPT_IGNORE, and using this env var works!

So, you can set this ENV before, or export it in your .bashrc or .zshrc, or use it inline when calling the gradle assembleRelease like this:

ANDROID_AAPT_IGNORE='!.svn:!.git:!.ds_store:!*.scc:.*:!CVS:!thumbs.db:!picasa.ini:!*~' ./gradlew assembleRelease