Best way to have multiple instances of soffice ?

I have a node server for generating reports and it has been using soffice in background to convert docx to pdf. But I often have 1000s of docs to convert for a single request and one instance is just not enough. What is the recommended way of having multiple instances I can distribute my workload across?

Use several (according to CPU number?) user profiles: -env:UserInstallation command line parameter controls that.