Is this a normal battery drain?

You do not need to go THAT low with the brightness. Between 30%-50% would be sufficient.

iPad battery is rated as UP to 10 hours, but that can widely vary.

If your battery drain in within between 5-10% per hour, this is considered normal.

Your 3% in 30 minutes is fine, but your screen brightness is turned down to an extreme.

You CAN crank up the brightness a little more than this.

You want the brightness reduced enough so you can still clearly see the screen and what you are doing with minimal eye strain, but not so bright to unnecessarily run down the battery.

Tap on the link below to my iDevice/iOS performance/optimisation/battery optimisation user tips link.

Slow iPad on iOS 11, 12, and iPadOS - Apple Community

Try all of these tips and leave each tip active together. Do not simply try every tip individually, expecting just one tip to be a performance “cure all”.

Many of these tips are designed to work together to help improve overall iOS/iDevice performance.

Best of Luck to You!`

No.

Heed the warning at the top of your battery settings.

What else do you do with an iPad that could be draining your iPad battery so fast?

Did you heed the warning at the top of the Battery page?

You need to turn down your screen brightness.

Battery listed the issue. Clear as day what you needed to do.