Personally, I'd like to keep the memes or shitposting kinda contained. Maybe a daily or weekly meme post. I really like how things are right now with the on-topic posts and discussions.
Might also need a bit of active moderation to remove duplicates posts and enforce some civility, though right now those aren't problems.
Daily discussion threads would be a good way to keep people engaged.
For the moderator situation, you can probably contact a site admin and bring it to their attention. They should be able to add extra mods (I know this because this situation came up for a community I created right before I went on vacation).