In the latest upgrade of Android Studio 4.1.3 for macOS has not worked Android Emulator due to missed IOUSBHost library. This problem actual for macOS Mojave and below. During the attempt to run AVD you are getting an error: "The emulator process for AVD was killed".
On this issue created up a bug report. If you upgraded and encountered with this problem though, please, give them know by the link above.
If you have no time to wait fixes and have not physical device for testing, then you have not any other variants except one - downgrade, that described here.
UPD 2021-04-02: Fixed in Android Emulator 30.5.4.