My idea was to run a automation when the TV went off. I decided to get an Kasa HS110 plug w/ energy monitoring. But as DNS was invented because remembering arbitrary numbers sucks, I didn't want to base automations off of "energy draw" but, "on/off". So I made a Binary AKA Boolean sensor with a threshold to monitor the energy sensor. I actually did this before I got my smart plug, so for a demo I used my thermostats "setpoint" and made a horizontal stack card and changed the setpoint and watched the correlating binary sensor entity status.
Like so: Note: On > 20, Off < 20
Worth looking into → https://www.home-assistant.io/integrations/utility_meter/