Very cool! Have you considered adding UGC features like user-generated skins or mod content? I have a start up called Asset Layer (https://www.assetlayer.com/) which makes it simple to add these types of features to small indie games. We focus primarily on Unity but are working towards a UE5 integration as well.
I'd love to connect and learn more about the types of features you find interesting and see if theres a way we could help you execute on them.