OK, Thread uses IEEE 802.15.4 (just like ZigBeww), most of its channels operate within 2.4GHz spectrum. HomePod mini has had Thread support since 2021, and looking at iFixit teardown, it uses SKY66404-11 for ZigBee/Thread/Bluetooth:
https://www.ifixit.com/Guide/HomePod+Mini+IC+Identification/...