I use the Spotify Android App to stream into a Chromecast Audio which is plugged into a 15yr old Sony Hi-fi.
This outputs to a multiway speaker switch, and decent wiring goes up some sleek trunking to the loft.
Lounge has the original hi-fi speakers, bedroom is another set of standard speakers, kitchen and dining rooms have a pair of moisture resistant ceiling speakers which are much better than expected.
Cheap, simple, and as a bonus, I can control the tunes when I go to bed with a sleep timer on the hifi, and then it wakes me up to the radio in the morning.
The only real downside to the whole set up is the volume isn’t adjustable to suit each room, but you can adjust it from the phone easily.