I use a Chromecast audio on my in ceiling / whole-home speaker system. As it will still work for a few more years, I'm not in any hurry to replace it. In the next year or two I expect there will be plenty of options for replacements.
Obviously if Google does something goofy and actually makes the Chromecast Audio cease functioning, then I would have to decide sooner.
If I had to decide today, it would just be another chromecast or Google Assistant based device with a 3.5mm headphone jack.
