30w adapter charging

Base model iPads, like your 8th gen iPad, cannot fast charge.

The 5th, 6th, 7th and 8th gen base model iPads cannot fast charge with any Apple power/charging adapter block.

Most iPad Pro models and the iPad Air 3 and 4 CAN fast charge with a higher wattage Apple power/charging adapter block.

You can use ANY Apple power/charging adapter with any iOS device.

So, yes, you can use that Apple 30 W power/charging adapter block with your 8th gen iPad.

Your 8th gen iPad will only take the amount of charge power that it needs/requires to charge and that is it!

No worries.

“Fast charge”? No. iPads do not fast charge. iPhones do.

You can charge your iPad with this adapter.

Charge your iPhone with an iPad or Mac notebook power adapter - Apple Support