Siri Remote IR control of TV and AV/soundbar POWER

Just set up new Apple TV 4K and read online about Siri remote controlling AV equipment. So far I've only been able to control AV system volume with the Siri remote. I cannot power on/off the soundbar via IR with the Siri remote, forcing me to still have a second remote to turn on the equipment before using the Siri remote to control volume.

Background: Apple TV connected via HDMI to a Panasonic TC-PZT60 with Bose Cinemate 1 SR connected to the TV via optical audio (TV cannot control/power-on the soundbar since optical audio only transmits the audio signal).

The Panasonic TV seems not to support HDMI CEC because it does not turn on when waking the Apple TV. I really want to use the Siri remote to control everything, and felt like that should be possible since the Siri remote supports IR, but I don't understand why you cannot use the IR transmitter that is already in the remote to control power to both a TV and soundbar/AV equipment. It seems backwards to only allow volume control via IR, rather than power and volume control, since if you need IR to control the volume of AV equipment, you likely also need IR to turn on/off the same equipment.

The TiVos that I'm replacing with Apple TVs allows you to setup the TiVo remote power button to send 2 separate power signals to both the TV and soundbar. This seems like a very simple update to implement to the Siri remote since the hardware is already there. Adding 2 separate power-on IR signals when pressing the menu button to wake up Apple TV would be extremely helpful to those trying to simplify their remote control collections by switching to Apple TV.