Try and boot the Mac in the safe mode to see if there is an external app that is draining your battery
- On your Mac, choose Apple menu > Shut Down.
- Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.
- Press and hold the power button on your Mac until “Loading startup options” appears.
- Select a volume.
- Press and hold the Shift key, then click Continue in Safe Mode.
- The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.
if the battery is not draining in safe mode, the drainage is caused by an external app, please review the apps that you've running on your MacBook