It seems a natural issue for Bluetooth audio system.
(It usually works with hands-free audio system via bluetooth device)
should be separated Audio and Mic for clear audio sound.

Please check this way, Audio through Bluetooth ear-phone as like Airpods and Mic through wired Mic (External) or other mic device.
And also set in Discord separately.

It will make clear sound without any problem with mic.

Sorry for my poor english, in advance.