My iPad will not complete

If you are experiencing difficulty backing-up your iPad to iCloud, start here:

If you can't back up to iCloud - Apple Support

While you will need a stable network connection for the backup to complete, other than how long the backup will take to complete, the actual network bearer (WiFi, Cellular - or via a VPN connection) should have little direct impact upon the backup process.

Unless you have insufficient space within which to store the backup, with a stable network connection - if the backup starts - it should be able finish.

You need adequate iCloud storage. Your iPad requires an adequate charge. The Wi-Fi should have no VPN, no Hotspot, no anti-virus. The iPad should be relatively free of activity.