Do I understand correctly that the NPCs only reappear after the daily restart of the server and not, for example, 15 minutes after I kill them?
Or do I just not see the option to set the respawn time?

Currently the entities will only respawn when the plugin reloads, which happens when you restart the server for example. There is no timer logic to respawn them as they are not expected to be killed/destroyed.

I honestly didn't expect people to use this to spawn NPCs. Can you tell me more about your use case? For example, which NPCs, and for which purpose? Do you expect the NPCs to be invulnerable, or do you want players to kill them and then auto respawn them periodically?

We would also like to place scientists at the small monuments that appear regularly and can be defeated. To increase the level of difficulty on a PVE server.

Thanks for the info. Introducing something like that will likely not fit easily into the current implementation since it's not simply a one-and-done entity. Therefore, I will have to do some research on how best to implement that sort of thing. It may turn out that it should be implemented in another plugin focused on adding NPC spawn points.

No ETA on when that will be implemented since I have a number of ongoing projects. Folks can feel free to chime in if they have ideas or suggestions on how to design and implement this.

I have also renamed the thread to clarify the suggestion based on my understanding.

I just released a feature in v0.11.0 for spawn points, which are very flexible ways to spawn arbitrary destructible entities on a schedule. It's possible to spawn NPCs, but I've noticed some issues with their roaming behavior, which I plan to improve in future updates. I encourage you to try it out in order to help identify issues and opportunities for improvement.