Becoming a Villain: Harem? I'm not the protagonist, I'm the villain.

If you are curious, I will give a brief synopsis of this book. So a man transmigrates to another world, there he becomes the main villain, and there there is also a protagonist. The story will focus on the main character, there may be several chapters that focus on side characters or supporting characters for the storyline. Please don't expect me to update the chapter I don't want you to be disappointed, I'm just a beginner writer who wants to try writing a novel, maybe there will be lots of language or spelling errors, Also English is not my main language. Currently I'm looking for material and a plot for a story, because character development starting from weak to strong is quite difficult, and again this will be my first original book. Note: I was also planning to make a Genshin Impact fanfic, but because there are so many mysteries in the game I decided to postpone it, and thought about making my original story first.