@lucas_dnts i too had some concerns about the Googleservices.json file.
But what i did is,
→ uploaded a dummy googleservices.json file (without any data) to the kodular creator inorder to build the app.
→ keep the original googleservices.json file in my own server or google drive or anywhere you wish. (should be downloadable)
→ Using below extension, when screen1 initialize delete the googleservices.json dummy file and download the original file from your server and make sure to name it as (google-services.json) and it will save to App Specific Directory. (use the file Download URL in obfuscated text, but use of any encryption extension is recommended [I use free DeepHost Encryption extension)
→ now your original googleservices.json file will not be in your APK, but will be usable by your app.
→ I Suggest that this tutorial is applicable not only for JSON file but also for all ASSESTS files in the app which makes it safe & secure.