I suggest contacting/reaching out to Apple Product support and services.
Tap on the first link below and scroll down some to get to the Apple Product Support section and phone numbers for your location/region.
https://www.apple.com/contact/
OR
https://support.apple.com/en-us/HT201232
If you need to, if initial 1st tier Apple customer support is of no help to you, you can calmly ask to have this issue escalated up to more responsible, senior level Apple customer support employees to see if they can come up with other possible advice/solutions to your iPad battery issue, but I make no guarantees, whatsoever.
If need be, you can have your iPad issues escalated all the way up the chain to Apple engineering level customer phone support.
Even if no acceptable resolution, Apple, AT LEAST, logs all support calls and issues.
Also, if possible, bring this iPad to your nearest, open Apple Store location. Some Apple Store locations have re-opened.
Best of Luck to You!