Not getting Airplay Receiver to show up

Hi, I've been struggling with this now for a couple of days and don't know where I'm going wrong.
I'm on a iMac 27 in from late 2015 (17,1) and I've been able to upgrade to Sequoia with OCLP (2.12), hoping that this will solve the airplay receiver issue.

I've enabled feature lock, rebuilt and installed OCLP and rebooted, but still nothing coming up.
I've also disabled "Allow native models" since it should be a supported Mac. It was enabled before and didn't make any difference.

I'm losing my mind here, anyone that can help with a step by step of what to do? I'm new to this so might be going wrong somewhere.

Thanks!

https://preview.redd.it/6p7w927lsz2e1.png?width=996&format=png&auto=webp&s=c3ce70bd7f0528c901aeef28830d4223e0ddf43d