Take a look at the home assistant voice preview device.

It has a 3.5mm jack out to connect to better speakers. You should be able to integrate some aspect of audio playback.

From the FAQ

Can I play music on this device?

Yes, if you plug an external speaker into the 3.5mm audio port. The built-in speaker is meant for voice feedback and is not optimized for listening to music, but the included DAC is capable of playing lossless audio on a suitable external speaker. We recommend using Music Assistant to control music playback.

Good to know, thanks!

I’m not sure about self hosted specific. There is a device called WiiM. Works with most of the major streaming services. I believe they’re also working on plexamp integration too.

I’m guessing the author is getting some kind of referral to send them to that other site that hosts grafana. Because home assistant has a 3rd party app for grafana built in. Granted it would be a few more steps than they outlined, but it’s also not sending your data to some random company.