When a third party antivirus is installed by the user, Microsoft Windows disables the Windows Defender antivirus to avoid conflict.
Now, I don't use Avast One Essential (but Avast Antivirus Free), but the same should happen. I don't know why it would have been an auto start entry after a 3rd party antivirus is installed.
I also use Windows 10, but it should be the same in Windows 11.