Step 1. Buy or own a phone with a built-in infrared transmitter.
My preferred choice, at the moment, is a Samsung Galaxy S5, which has a removable battery, support for the newest version of Android (Pie) via LineageOS, and can be bought from eBay for <$100.
Step 2. Install TV Kill.
The app sequentially goes through the off codes of all major TV models. It even has a mode to keep cycling repeatedly through the codes until you stop it.
Enjoy the silence, and you’re welcome.