A:AnswerAll keyboard in the 21st century will be using a usb cable. HDMI (High Definition Multiedia Interface) is gonna be used for your graphical output such as a monitor or tv.
A:AnswerI don’t think they can be. I found this “The Apex 3 uses proprietary keycaps that cannot be removed or replaced.”
Maybe check out mechanical keyboards like the Logitech G610
A:AnswerYou can change the colors and they letters themselves don’t light up but the keys underneath do light up and I’m not sure if it’ll connect you could YouTube it to find out what keyboards do connect