Here's a suggestion. Add the MEE6 bot the discord server. Wheneven i visit it's dead and pretty bland to look at. What MEE6 does is it ranks people by giving them a score of 15 - 25 XP points per message. To stop flood, you only get xp once a minute. You need xp to level up. It also does stuff like delete messages, give permissions blah blah blah
To make people talk more there, you can set up the bot in such a way that it gives roles to people with certain perks. Examples:
You need to type !readrules in #welcome channel to get access to other channels.
You need to type !addquiz in #bot-cpmmands to gain access to the #quiz channel
@Newbie Trainer - level 5 and below
@Trainer - Level 5 (can use global emotes)
@Veteran Trainer - level 15
@Master Trainer - level 25 (access to secret channel)
@Grand Master - level 50 and beyond (send links and upload images)
@Quizzers - people who did !addquiz
This would motivate people to talk more to get the higher role. Hence, more activity
At a point, it asks for 5$/monthly for certain features, but that's up to you.