I'd suggest to reward active users with points and/or for those who stay in the channel as it would draw more attention to the channel and would increase population. Defending the "stay in the channel" from proxies would be to put roles on verified members like in the page let's say via steam or verified discord accounts.
We have had such a system in the past - users received 1 point for writing a message, and then there was a 1-minute-cooldown after that. But it didn't work so well, even long-time members just spammed stuff for fun. And newer members abused it heavily. It caused more issues than it was doing good, so we are currently not considering adding something like that again.