Well, a frequent theme in Homelander fanfic is his relationship with other characters. This could be his relationship with the other members of The Seven, or his interactions with normal people. It shows how his presence affects those around him. Another common theme is his origin story. Writers often like to create their own versions of how he became the Homelander we know. And the theme of his mental state is also common, like his megalomania and how it developed over time.
One popular Homelander fanfic is 'The True Nature of Homelander'. It delves into his backstory and what might have made him the way he is. Another is 'Homelander's Redemption Arc' which explores the possibility of him changing for the better. There's also 'Homelander in an Alternate Universe' which places him in a different setting and shows how his character might develop differently.
One common theme is power dynamics. Since Homelander is extremely powerful, the fanfics often explore how the reader relates to that power. Another theme is redemption. Many stories try to show if the reader can lead Homelander to a path of redemption. And there's also the theme of love against all odds, as Homelander has a very complex personality.
Definitely. The comic version of Homelander is portrayed as having greater strength and capabilities. This is evident in his confrontations and the scale of his power displays throughout the comic series.