Rocker switch box for the front of the Ender 3 that works with these https://www.amazon.com/gp/product/B07QKFD7Z7/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I have the PSU power to the main board switched through here so that I can control it from the front and also power other devices (like a RPi) from the PSU without shutting everything off