The vacuum cleaner provides an external source of flow going through two holes in the pipe. Why should there be a force on the pipe as would happen if gas contained inside it was expelled from one end? These are entirely different systems. The one example has no bearing on the other.

Similarly, your conclusion is incorrect with the equations. Velocity is inherent to both mass flow rate and volumetric flow rate. But I don't see how this has anything to do with your vacuum cleaner example and conclusion.

Force is proportional to mass flow rate, yes. And? There is nothing here.