Readest is an open-source, cross-platform e-book reader with a beautiful interface and several color themes — the main reason I recommend it.
Readest lets you highlight text and take notes; exported notes are Markdown and reading progress syncs across devices via your account. It supports parallel reading (two books side by side in split view), and you can select words or sentences to translate them.
You can also free your hands with text-to-speech and let Readest read books aloud.
Note: the demo animation uses the official macOS screenshots. I provide a portable Windows build — open and run, and it shows Chinese if your system language is Chinese, or switch as you like.