I like the Wiim but in your particular case you might be better served by Apple TV, which costs around $50 more. Your iTunes files should appear on Apple Music app, but you might need to pay the Apple Music monthly fee (I use Apple Music as my streaming service so I don’t know what the deal is for ATV owners who don’t pay for the streaming service-if you use a Mac PC you can probably answer this yourself). YT is free on ATV. You can get some Internet Radio with free apps.
ATV sounds better than Bluetooth. Presumably your iTunes files are mp3 equivalent, YT and Internet Radio generally are mp3 or worse, so ATV should sound ok. If you don’t have a monitor to attach to the ATV (if your computer has HDMI input then use that), an iAd or iPhone can be used as a controlling remote for ATV