Most Apple stores, worldwide, DO NOT actually repair iPads.
To expedite quick and speedy customer service, most Apple Store ONLY offer in/out-of-warranty device replacement, in lieu of an actual repair or battery replacement.
Apple charges $99 U.S.D., plus tax, for a battery replacement which would,,normally, would consist of a device replacement, in lieu of an actually teardown and battery replacement inside of an iPad.
This is not a huge amount for a battery replacement on this old an iPad.
The potential problem is with the 2015-2017 iPad Pro models is Apple stores need to have replacement devices ( probably refurbished models ) of these 5 to 7-year old iPad models to swap out for the battery replacement service.
Apple Stores may not have any models this old to simply swap out and Apple stores may not want to actually do a real teardown and battery replacement on these 5 to 7-year old models.
I am not even sure if Apple and Apple stores will still service device swap or actual repair of 2014 iPad Air 2 and iPad Mini 4 models that are, currently, still supported.
Apple lists this iPad model as Vintage, even though these iPad Pro models still support iPadOS 16.
You would need to search online to locate and call contact your nearest, “local” Apple Store location to try/attempt to make an appointment to get your Apple iPad diagnosed and options presented to you
OR, alternatively, use the “Get Support” link, at the upper right hand corner of every Apple Support Community Webpage to attempt to schedule an appointment with your nearest Apple Store location.
Apple Store employees will be glad to help/assist you.
Best of Luck to You!
