How to get ChromeCast working with IOT VLAN?

As the title says I’m just trying to get my chromecast to start working. I followed the Beginner's Guide to Set Up a Home Network Using OPNsense and put all my IOT devices on my UNTRUSTED VLAN, but all my personal devices (phone, NAS with photo storage and media, etc) on my TRUSTED untagged LAN. I’ve tried using mDNS repeater and UDP Broadcast Relay to get it working, but can’t figure it out on my own and couldn’t find any guides online. Has anyone gotten this to work?