The main other alternative we looked at was Discuit. It had the benefit of being very similar to Reddit in terms of UI and being pretty polished, but the activity just wasn't there. We also looked at Lemmy, which is the most popular Reddit alternative, but we weren't particularly huge fans of the UI.
In the end, we chose Kbin because we really liked the UI and it's federated with Lemmy, meaning you aren't missing out on whatever's going in Lemmy communities.
Trying to be reddit and starting out with a slew of rules are both bad ideas. Loosen up and invite people to talk about things that are Not welcome on reddit, ffs.