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.
We could do this similarly to another server, but with some alterations: active people are proposed to higher-ranked staff to earn a steam key with varying levels of value, with a review of the messages that caused the proposal. If admins think all is good, the person is rewarded. If not, nothing happens.
There could also be a reputation system, based off of how fast people send messages and whether their proposals have been accepted a lot or denied a lot.
To prevent abuse of this, one of two systems could be employed: