How to properly set up multiple PreStage Enrollments?

We use multiple PreStage Enrolments in our environment. One for staff devices, one for student devices, etc.

We have one DEP instance which automatically assigns all devices to the staff PreStage. If the device is for student use, this requires manually removing from the staff PreStage and activating it in the student PreStage. Yes, a bit of a pain when it happens but it's not that often so I live with it!

The only way around this (someone correct me if i'm wrong) is to not auto assign to a PreStage and manually assign from the DEP portal based on a list of serial numbers or PO numbers.

We have multiple PreStage Enrollments as well; one for staff, one for our 1:1 take-home, and another for on-prem student devices. We don't automatically assign - we upload multiple CSVs of serial numbers in DEP and assign to the JSS in batches - first for staff, then we assign all unassigned to that PreStage. Then we move on to the take-home devices, assigning all unassigned to that PreStage, etc. It involves going into the PreStage and clicking on the check box to highlight that whole page of devices, filtered to show unassigned. It worked smoothly for us; we just started a new JSS instance when we transitioned to cloud-hosted after purchasing almost 1000 new devices and transitioning 400+ from our old on-prem server to jamfcloud.

You don't have to create another MDM server.
You don't need to create another DEP.
You just need to setup another PreStage Enrolment with a scope that will only include your tvOS devices. You can always check the scope for what devices will be targeted before you push the settings live by clicking on Scope and looking through. So have a play with it and see what works best for you.