Why this is difficult on macOS
macOS can remember and connect to many Bluetooth accessories, but the normal sound output picker is built around choosing one output device. When two people want to listen from one Mac, you need a way to route and synchronize the same audio across more than one device.
Use SoundShare for multiple Bluetooth headphones
Supported listening setups
SoundShare is useful for AirPods, AirPods Pro, Beats, Bluetooth earbuds, Bluetooth headphones, and Bluetooth speakers. It is especially helpful when two people want to watch a movie on a MacBook, listen to music while traveling, or share a podcast without disturbing people nearby.
A realistic note about Bluetooth latency
Bluetooth latency can vary depending on the headphones model, codec behavior, Mac model, battery level, and wireless environment. SoundShare is built to keep the connected devices synchronized, but any Bluetooth setup can still have some inherent delay.