A distinction is made by HPS Lydia in the following article: https://ancient-forums.com/threads/my-life-journey-to-our-gods.298504/ but I didn't know there was a difference.
Is a Daemon someone who has newly acquired the Magnum Opus, such as HPS Pythia?
The term "demon" has various meanings. In Homer it refers to a divine power that can manifest itself on human destinies. In Plato's writings, the role of the Daimon is explained as an intermediary with the Divine, to enable man to access and better understand it.
This also relates to the writings of Hesiod who reports of the men of the Golden Age, the "benevolent Daimones on Earth guardians of mortal men" by "the will of Zeus." These demonic beings dispensed wealth on earth by considering who was righteous and who was not. They were called "epichthonioi" because they operated among the Earth, unlike the powers of the "celestial" Gods whose sphere of activity resides in realms inaccessible to this world.