Well done, thx!
Some hints, maybe could be helpfull:
1- key creation at google as described here:
https://github.com/anxdpanic/plugin.vide...-150931901
2- login with your google account (mobile account must be available!)
3- create an API key and two client IDs. This will later result in a double query when logging in.
4- the keys can be entered in the addon-fields or directly in api_keys.json and settings.xml (/storage/.kodi/userdata/addon_data/plugin.video.youtube). YT-addon must not be active. If the files are not available, enter simple fake keys in the YT-addon settings. A client ID like "228xxx68yyy-ur8n3xxxcb1cccv3jm7tjagd9eh0vvvvv.apps.googleusercontent.com" should be entered without ".apps.googleusercontent.com".
5- still in Kodi, still in the YT-addon, sign in: YT will will ask you to sign in twice and register your device twice with code sent to your mail-account.
The second time you connect a device, you will be prompted with:
"This app isn't verified. This app hasn't been verified by Google yet. Only proceed if you know and trust the developer."
From there clicking Advanced and Go to <your project name> (unsafe) allows you to complete the process.
cu