Yes, I bought a Logitech Bluetooth audio receiver. I can now watch all Netflix, Disney plus and YouTube films via my old Technics audio system without any problems. Projector does not need a video cable (connected via wifi) or audio cable. Just a power cable, that's all. Simply ingenious!
Yes, you can. I have connected my stereo system with a Bluetooth adapter. I don't have any problems with time shifting. Otherwise, this can also be set with [AV Sync. Adjust].
I first connected a UE Boom via Bluetooth. However, the sound played about half a second after the picture. This was annoying for me in the long run. Finally, I connected another speaker via HDMI. Picture and sound are now in sync.