I was confused to which example you were referring to
As already covered, onAuthorised returns the channelID.
In an ideal world you’d do everything by ID, to account for name changes.
But if you have the channelID from the JWT, and a service, and an app access token, you can get the channel name from the users API (A user is a channel and a channel is a user)
And the profile extension becomes a channel profile extension
You’ll need a relay server, which I though you had since you referenced a database.
As otherwise there’s no way to reach the gamer’s PC (ignoring opening holes in the firewall and leaking the streamers IP address and the fact you need a SSL Cert)