How to build custom Capacitor 3 plugin and access Java class from another plugin in node_modules

Question

I am building a custom capacitor plugin with:

npm init @capacitor/plugin

This creates my plugin but following the directions it says to run: npx cap sync

But I get this error: npm ERR! could not determine executable to run

I'm just adding this info as I'm not sure if it affects anything...

So I created my Java class in Android studio (AS) to extend capacitor-push-notifications. All this works in AS but I wanted to create a plugin so if something happens to the android folder I can rely on my plugin to add the Java files.

I import the file (in Java): import com.capacitorjs.plugins.pushnotifications.PushNotificationsPlugin

My question is: How do I import the capacitor-push-notifications when I am in VS Code? I get the following error when I run npm run verify:android:

 Could not find com.capacitorjs.plugins.pushnotifications:pushnotifications:1.0.9.
 Required by:
     project :

also, I did install the plugin: npm i @capacitor/push-notifications

also added this to build.gradle under dependancies: implementation "com.capacitorjs.plugins.pushnotifications:pushnotifications:1.0.9"

So do I just ignore the error as I know it works in AS? I looked everywhere and cannot find any reference to this.