Possible to run commands after npm start on the same console?

Generally in unix-systems (must been also windows but not sure how) you can run a process in background with:

command &

So in your case

npm run &

The downside is, you can't kill the process by cntrl-c. You need the process-id (PID) to kill the process. Lets asume the PID is 12345 then you need to do

kill 12345