I don’t know enough about HDMI and associated splitters to comment. Worth a try, and you’ll have the Zone 2 option as a back-up.
Regards,
Wayne A. Pflughaupt
From the manual it looks like you have 2 HDMI outputs. You might be able to use the second one for this. Connect it to an HDMI audio extractor to get signal to your transmitter.
See pp. 30-01 of the manual...
What you need is a Bluetooth transmitter. The Avantree Oasis seems to be one of the better ones. Its stereo 3.5 mm input would connect to the Pioneer’s main RCA outputs, using a stereo RCA to 3.5 mm cable. The only possible caveat, some AVRs disconnect the front speakers if you plug a cable...