Jason Bayton has a great recent infographic that details the different available Android Enterprise enrollment mechanisms:
Under QR code base enrollment note that he calls out that the QR reader isn't baked into the OS until Android 9.0 which means the devices actually have to connect to WiFi BEFORE they can scan a QR code using that enrollment process. This can be a relatively frustrating from a bulk enrollment standpoint as you may have to manually connect the devices to a wireless network with access to the Play Store (for automatic QR reader download). Even though the MobiStage app allows you to bake in WiFi settings into the barcode you can't technically leverage that until the QR reader is installed which is kind of a cart before the horse situation. An open staging WiFi network is often leveraged in these situations before a device then ultimately is provisioned to connect to a production network.
If you want to bypass the Google setup wizard and minimize the amount of manual touches you can actually use a custom Zebra barcode on the Zebra Android devices to bypass the wizard and automatically launch StageNow. You can then use StageNow to perform the Android Enterprise enrollment, even for DO enrollment. This is somewhat of a big differentiator for Zebra Android devices as you typically can only enroll as a work managed COSU DO device through the Setup wizard (QR, NFC, or token/hashtag) or through ZTE.
Longstory short I think you may want to explore using the barcode based GMS wizard bypass and then StageNow based enrollment in order to limit user interaction during the enrollment process. I think ZTE would be more ideal but if you've already acquired these 3000 devices it might be too late for that. Then again, I don't have any firsthand exposure to ZTE yet.
I currently do not have a Zebra TC25 device with me to test out, but in general, for enrolling brand-new devices in Android Enterprise managed-device mode, you can try the following:
1. Open the box and turn on the device.
2. Optionally change the language to be used (but don't advance to the following screen).
3. Tap your device screen (on the same page for optionally changing language) six times. There should be prompt to enroll with QR code (with on-device camera) or NFC bumping (with a parent provisioning device running MobiControl Stage app).