How do I make the enemies respawn?

Hi guys

I would like to make every time you go to a save point the enemies respawn as in the beginning in the same place.

For example, Dark Souls. Every time you go to a bonfire, all enemies are restored as in the beginning.

But only enemies, I don't want reset all layout.

A layout resets by default right when you enter it so what do you have going on so far to stop enemies being created on entering a layout, persist behaviour?

Is it one layout or several layouts?

Do more difficult enemies spawn or is it the same enemy type?

What should happen if you progress without killing the enemies and go back?

What happens to enemies that you haven't reached yet that are beyond the save point?