Your reply suggests you didn’t write the initial code, so you might have issues making all the changes. Since I’m not giving the full answer but links to the documentation so you can fix it yourself
You will need to either follow what the migration guide says
https://dev.twitch.tv/docs/v5/guides/migration/#username-versus-user-id
Of what the Twitch API v5 Gude says
For converting from a name to a ID.
The code suggests that a command of !add username is run in discord. You’ll need to add code to take that username and convert it to a userID and store that along with the channelName