Discuss about the function of Aegisthus in the play: call it The Aegisthus Effect. (a) Why is he absent until the very end?

the function of Aegisthus in the play: call it The Aegisthus Effect. (a) Why is he
absent until the very end? (b) What if there was no ‘partner’ for Clytemnestra and she was (like
Penelope) alone? Or (c) what if her SO was someone else?

Link:
https://antilogicalism.com/wp-content/uploads/2017/07/aeschlyus.pdf