Make a .wslconfig file in your C:\Users\username folder.
In this file you can set mulitple parameters, see following options:
[wsl2]
kernel= # An absolute Windows path to a custom Linux kernel.
memory= # How much memory to assign to the WSL2 VM.
processors= # How many processors to assign to the WSL2 VM.
swap= # How much swap space to add to the WSL2 VM. 0 for no swap file.
swapFile= # An absolute Windows path to the swap vhd.
localhostForwarding= # Boolean specifying if ports bound to wildcard or localhost in the WSL2 VM should be connectable from the host via localhost:port (default true).
# N.B.
# entries must be absolute Windows paths with escaped backslashes, for example C:\\Users\\username\\kernel
# entries must be size followed by unit, for example 8GB or 512MB
Example usage:
[wsl2]
memory= 6GB
To limit WSL2 (and therefore the vmmem process) to 6GB of RAM.