Assuming you’re ok with connecting your receiver to the network, you should be able to wake the receiver if you detect the tv is on without any cables at all - if your tv is also on the network (I’ve got a home assistant automation doing exactly that) or you can use a $10 smart plug with power metering.

That said props for actually using HDMI-CEC! And it’s cheaper than most smart plugs (and probably safer, too)