What kernel function returns process statistics either for the current
process or for the specified process?

(For the latter, I would pass the result from GetCurrentProcessID.)

Currently, I am only interested in the Mem Usage and VM Size for the
current process, as they are called in Task Manager.

So if there is only a function that returns memory usage information
for the current or specified process, that will do.

Please provide the function declaration to use in VBA.