Really? Usually when a new game is ported to new engine the amount of content on the new engine is very less...
I appreciate the sandbox elements, but am I missing out on any story elements if there any present in the game?
They did have a fuller sandbox world map in the UE4 version, but they wanted to go in a different direction on that anyway so it was left behind when they changed engines. The UE4 version is no longer in development, so all of the newer sex scenes, characters, models, etc. are in the UE5 version. The only "story" elements the UE4 version had were a sort of tutorial/demo where you start at a crashed ship, visit a village, and have sex with the villagers. I haven't checked in a while but I think that part might still be included. Otherwise it's all just "mechanical" elements: sex scenes, model viewing, character customization, etc. The stated intent from the developer is to get these interactive components and tools working first and then build a story using them. I know it means long delays before there's anything narrative in the game, but this is the better way to do it, otherwise they run the risk of having woven a story/quests with the parts they previously developed and then having to change some critical underlying component and suddenly all sorts of things break and can't be fixed without basically starting over.
That all said, the sex scenes are really good, so it's fun to try it for that alone, I feel.