Alternatively you could buy something like the Yamaha MusicCast WXAD-10. It’s a little Spotify Connect enabled box that you plug your speakers into and it has a price tag of about 140 EUR in Europe ($160).

I haven’t tested it or listened to it myself but the first and only review I checked was favorable.

https://europe.yamaha.com/en/products/audio_visual/accessori...

https://www.avforums.com/review/yamaha-wxad-10-musiccast-ada...

Likewise, a lot of AV receivers come with Spotify Connect these days. For example, Onkyo TX-NR585 ($380) which was recommended by CNET.

https://www.onkyousa.com/Products/model.php?m=TX-NR585&class...

https://www.cnet.com/topics/av-receivers/best-av-receivers/

That’s not to say that one should buy an AV receiver for this purpose alone. I only mentioned it because (a) some people might have a Spotify Connect capable receiver already without being aware of it or (b) they are planning on buying a receiver anyway and so might wish to consider this alongside their other criteria.

You could also use a chromecast audio, which should work with spotify: https://www.spotify.com/en/chromecastaudio/