Why is my iPad mini 7 stuck at 5% during 18.3.1 update?

See If you see an error when you update or restore your iPhone, iPad, or iPod - Apple Support

You would be best advised to always keep iPad connected to its Power Adapter (or other external power source) throughout the update process.

Doing so serves two purposes...:

1) The iPad's WIFi connection remains active - and the iPad CPU running a peak performance.

2) The Power Adapter ensures that the update process will not fail due to a battery issue, such as low charge or a battery fault.

iPad mini here too and mine has done exactly the same. It's well and truly in the doom loop; won't update, so hard reset, forces me to connect to my computer, where it tells me to update or restore, I choose restore and then it tells me I have to "restore AND update", where we go back to "won't update".

I have noticed when it hits the 5% update bar, iTunes shuts itself down on my laptop.

I've spoken with chat support and now I have to take my iPad in on Monday.

First apple product I've had in a decade... quickly remembering why I stopped using them.