The time required will be determined by many factors, including but not limited to:
- how much data must be restored
- the speed/throughput of your internet connection
- the speed/throughput of your WiFi network
- server loading; assuming an iCloud backup, Apple’s regional servers may be busy
The only aspect that you may be able to directly influence is your WiFi network. You should note, however, that the slowest item in the chain will ultimately be the limiting factor.
Your description suggests that something has stalled with the process, perhaps due to an interruption of the network connection or along its path to Apple's servers. you may find that a restart of your WiFi Router, followed by a restart of your iPad will clear the problem….
To restart your router, disconnect power from the router for at least 30 seconds - then reconnect power to restart. After your router reboots (which may take several minutes), force restart your iPad:
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)
Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

Keep your iPad connected to its Power Adapter throughout the restore process - as doing so will help to keep the iPad's WiFi connection active.