Yes, you can connect your older Sony headphones (TMR-RF855R) via Bluetooth to the Ugreen CM403 adapter and your Samsung TV (UE55DU7172UXXH). The Ugreen CM403 is a 2-in-1 Bluetooth adapter that functions as both a transmitter and receiver and is compatible with devices with a 3.5 mm AUX connection. You do not need an RCA-HDMI adapter as the CM403 works directly via the 3.5 mm connection. Note, however, that the CM403 is not compatible with AirPods Pro 2, but this should not be a problem with your Sony headphones.