5.8GHz&5.2GHz Dual-Band Wireless Audio Transmitter Receiver for TV/PC, 160ft Long Range 0.018s Low Latency with Built-in 2.4G Bluetooth 5.3 Receiver, Wireless Adapter Kit with RCA(3.5mm) Out/Input

You can buy a cheap 5ghz transceiver pair and a small amplifier to go on the receiving end. Connect the wireless 5ghz transmitter to line level (preferably volume controlled) zone 2 outputs from your receiver, and connect the wireless receiver to the amplifier which you would then connect to your speakers. Examples: wireless transceiver: https://a.co/d/07PbccZ3Amp: https://a.co/d/093G0GwQ Or any amplifier on the receiving end. Something more powerful than the Fosi perhaps.