What is this qemu-system-aarch64 process and why is it using almost 3 GB of RAM on my M1 Mac
This process belongs to an application you've installed yourself. To find out more, select the process in Activity Monitor and press Cmd-I to open the Process Information window. You should see the name of the process which started it at the top, and the path to the binary itself near the top of the 3rd tab (open files and ports).