Question Setting up Apple Homepod mini with Roku

[r_scooter]

I bought a Apple Homepod mini and a Roku Express 4K+. The roku express says it is compatible with AirPlay however I can't get the audio from the Roku box to play from the Homepod mini. After contacting Apple support, and Roku support they both say it can't be done. Does anyone here have the know-how to aid with the setup?

Apple HomePod Mini

Roku Express 4K+