Some info on how you are setup for running unattended would be helpful to better answer your question
i.e. for myself
I have a Hyper-V running Win10 Desktop OS with SoapUI installed
I am using a ADO pipeline to an agent on my HyperV to pass over a command-line statement to
kick off my automation thru TestRunner. It will open up SoapUI, run my scripts, and then close SoapUI.
So I think if you look at the command-line syntax for running your ReadyAPI project
You should be able to start up TestRunner (which should get a float license) run your scripts, and close TestRunner (which should free your license)
SoapUI vs. ReadyAPI (SoapUI Pro) should both have similar command-line syntax for TestRunner
https://support.smartbear.com/readyapi/docs/functional/running/automating/cli.html
