Like one of these dinguses?

Airplay works for me but both my TV’s that I use Chromecasts also support Airplay. Also both TV’s have Bluetooth-compatible soundbars. If I didn’t have that I’d buy a cheap Bluetooth receiver that is compatible with my TV or whatever I’m using for speakers and connect via Bluetooth.

Edit: I’d buy this thing if I didn’t have Airplay or Bluetooth but did have RCA jacks.

Bluetooth Audio Adapter for Music Streaming Sound System, esinkin W29-us Wireless Audio Adapter Works with Smart Phones and Tablets, Wireless Adapter for Speakers https://www.amazon.com/dp/B016NUTG5K/ref=cm_sw_r_cp_api_i_bgiOFbEJSAFN9

Or a bluetooth receiver.

https://www.amazon.com/gp/product/B016NUTG5K

Volume levels going into the amp will then vary with the volume being changed on the CC remote.

It’s just a plug and play Bluetooth receiver. I have it plugged into the RCA jacks and it’s powered by the built in USB port. Everything you need right here https://www.amazon.com/dp/B016NUTG5K/ref=cm_sw_r_cp_api_glt_fabc_R34HGCY7YDBZKSG8EK1R?_encoding=UTF8&psc=1

I used these short RCA cables but they’re not necessary https://www.amazon.com/dp/B082VJQBZ2/ref=cm_sw_r_cp_api_glt_fabc_CW3R91KGWRKV7W9K5E3J?_encoding=UTF8&psc=1

If you have any Amazon Echo devices, you can pair it with Echo Link then connect it to your Denon.

If you just want Bluetooth and something cheap, this bluetooth receiver should do it

Seconded. However, for home use, a BT-Pro is overkill :) I'd just grab one of these cheapies.