Spotify on HomePod

Currently, you can't. To play music on a HomePod with Spotify you have to use AirPlay.

https://www.audfree.com/spotify-music/play-spotify-music-on-homepod.html

https://piunikaweb.com/2021/05/20/spotify-native-support-on-apple-homepod/

https://www.macrumors.com/2021/11/22/spotify-users-impatient-lack-homepod-support/

Hi adpenna,

Thank you for using Apple Support Communities. We understand you wish to have Siri play music on your HomePod from Spotify and we'd like to assist.

This resource will help: Play audio using Siri on HomePod - Apple Support

Specifically these steps:

"Add a music service to HomePod

You can play music from other supported music services on HomePod. Some music services require a subscription.

Note: Not all music services are supported on HomePod.

1. On your iOS or iPadOS device, sign in to the supported music service app.
2. In the music service app, go to settings, then add the music service to your HomePod.
3. In the Home app, tap , then tap Home Settings. 
4. Note: If you have more than one home, you see settings for your current home (based on your location). To edit a different home, tap Homes, then tap the home you want to edit.
5. Tap your user profile under People.
6. Under Media, tap the music service.

If you don’t want to use a music service with HomePod, you can remove it. In the Home app, tap , tap Home Settings, then tap your user profile. Tap the music service, then tap Remove from Home.

Set a default music service on HomePod

You can set a default music service on HomePod so that you don’t have to say the name of the service (Pandora, for example) when you ask Siri to play something. You can still play music from other supported services that you add to HomePod, too, by saying the name of the service when you make your Siri request.

To add a music service to HomePod, see the task above.

Note: Not all music services are supported on HomePod.

1. In the Home app, tap , then tap Home Settings. 
2. Note: If you have more than one home, you see settings for your current home (based on your location). To edit a different home, tap Homes, then tap the home you want to edit.
3. Tap your user profile under People.
4. Under Media, tap the music service you want to set as your default service.

You can also change which user account should be used when someone’s voice isn’t recognized. In the Home app on your iOS or iPadOS device, touch and hold a HomePod, scroll down, tap , then tap Primary User."

We hope this helps.

Cheers!