Streamer with decent app

yes its just a streamer/network bridge/ no DAC or Amp. but you can adjust volume from your device i.e.. phone. oh i reread and you did mention you wanted an all in one solution my mistake. well if you added an amp/DAC you’d be set i suppose.

Plenty of decent streamers many of which have been mentioned here. However a decent app is another issue altogether.  If you are a classical music listener Roon is the only app which gets it almost right. Apps from Aurender, Auralic, Elac or Cambridge Audio don't go close, especially if you stream Qobuz. The Qobuz native app, while not good, is as good if not better than the apps mentioned above but to use it on most streamers you need to go via Airplay which is limited to 44.1 sampling so no Hi Res. If you listen to music with a readily identifiable artist then almost any app will be OK at a basic level.

Bluesound app is not so good unless you like persistent queue.

Innous is very good.