Here is a link to the TV in question: https://www.amazon.ca/amazon-fire-tv-43-inch-omni-series-4k-smart-tv/dp/B08T6LD72Q

This is not for a Fire TV Stick or Fire TV Cube. This is for an Amazon Omni Fire TV (Fire TV is built-in to the TV). There is no IR command that I can assign to the power button. It requires a bluetooth command to turn on/off the TV.