I know I can use an HDMI source like a Raspberry Pi and a small screen for HDMI and could twist copper cable together and measure continuity through them to narrow down which is which but I’m wondering if there is an easier way. Maybe something I connect to either end?
You’re question sounds like you are running the wires. They make numbered stickers specifically for marking long pulls of wire so you don’t have to test them. Just wrap a number around both ends and voila. https://www.amazon.com/Gardner-Bender-42-029-Booklet-Identification/dp/B000VZM37C?dib=eyJ2IjoiMSJ9.ovuOUGMUj8C_DNFC00PsO15E6OyQQs4s4YRCRQ5SIvBh8TpdDH5nLU03qL-42bh-oOJCoVFYwVtUPeQlqhKnzvZMXHJ9RhzUumZprTY0Mrg_DQ7DSGe0DRcclV3BjnXeXLgg2Ko7AcPG_HShb6wik2ckoe52dNfzxqzSttiSrLzwENDsAQBJxsJx8g9lw-2GsDbb2IobpirvO78ZRERnIA.ZX5nJbb1fav8j3hRfA9xqgHVaHZf91iFrAY574w2q8k&dib_tag=se&keywords=wire+number+labels&qid=1731039683&sr=8-3