I have tried at least 5 types of spectating systems and none of them work as they should… and certainly not the free ones.
Most of them don’t include the extra feature of being able to hear the voices clearly and most of them don’t adapt well to Onesync and give a lot of connection problems to be able to access the players.
I’ve tried all of them and the only one that has worked correctly is this one, the one from Bit, its code is the only one I’ve managed to get working, because Bit is extremely good, really.
I highly recommend it.