Both the 9th & 10th generation iPads came with the Apple 20W USB-C power adapters and associated USB-C charging cable. Apple sells these separately as well.
The iPad's "charger" is actually built into the iPad itself. It controls the amount of current it requires to charge the internal battery that is coming from the power adapter. Ideally, you will want to use the Apple power adapter, but you could use any 18W, or greater, adapter with your iPad.
Apple power adapters and cables are extremely well made, and should be used when possible.
My suggestion would be that you consider getting a new power adapter & charging cable directly from Apple's online store. You will still need this, regardless if your iPad may require repair.
As far as the repair, only an Apple Technician can evaluate your device, and provide you with any repair cost estimates. Since you do not have an active AppleCare+ plan, these costs will be to you. However, if your iPad is less than one year old, and the Technician finds that this issue is due to a manufacturing defect, you may find that you can get a replacement device for little or no cost to you.