HomePod is plugged in, but not discovered by home app and shows no sign of life other than being warm

First of all is this a HomePod that previously worked or is it new and you’re trying to set it up?

• If you haven’t set it up yet please see: Set up HomePod - Apple Support and see the Apple Support article If you can’t set up HomePod or HomePod mini.
• if it was set up before and now not working, please try just restarting it first by unplugging for about 10 seconds then plug back in
• keep in mind to show up in your home app it needs to be signed into the same Apple ID you’re signed in with on the device you’re viewing the Home App on and is connected to a home wifi network.
• reboot your wifi by unplugging for about 30 seconds and plugging back in

If none of the above applies and you do want to Reset it see: Reset HomePod or HomePod mini - Apple Support