The best thing you can do to keep your community engaged is to simply talk more. I know I know.. it's not that simple! And to be honest, I'm personally terrible at it as I'm really bad at small talk. If that's the case for you too, consider hiring someone talkative. But nothing will compare to you doing it yourself.
Your investors want to know who is in charge. They want to be assured that they can trust you and talking to them as a real person can go a long way. Try to get to know them on a deeper level. Ask about their life and build up a relationship. They are more likely to keep checking in if there are interesting conversations happening.
Don't create too many channels in your discord as you want to keep the general chat as active as possible. Be seen. You need to be active and lead by example. So check in at all hours to see if there are any active members around who are up for a chat. In discord, using the @here command is a good way to bring people into the chat if there is a good conversation happening. Talk about yourself and your life. Give your members an insight into your world. This will help them open up too. You could do things like "@here post a pic of what you're looking at right now! This is my view:" Host events. In CastleNFT, we did a trivia night which was a lot of fun. You could do a general games night, trivia, poker, share your music night.. anything! BOTS • Points. One of the best things we did in CastleNFT was to add the bot 'Points'. It allows us to award points to our users for being active, engaging with our socials, winning games or anything else we choose. They can then spend their points in the shop. Stock the shop with custom roles, other prizes etc. They can also claim daily/weekly awards which is great as it encourages them to keep coming back. The free version is good enough but it does take a bit of time as you need to award points manually to each person.
• Trivia. This can be fun and there are a few trivia bots around.
• RPG This one can be really addictive. It certainly keeps people coming back and spending a lot of time in your server.
There are plenty of others and a simple google search of discord bots will give you many to choose from.