Don't buy smart speakers. Just buy regular speakers. Then you can plug them into whatever you like, run whatever software you like (e.g. pi musicbox) etc. So you actually own them, and they should serve you well for many years, for whatever you may need.
Also don't buy soundbars. Speakers don't want to be long and skinny. You'll end up paying a lot more for a lot less sound.
Also consumer grade speakers are often more expensive for crappier sound. Look into professional models, like studio monitors. For example, JBL 305PMKII. You may be able to find a local store where you can listen to studio monitors before purchasing.