A 2012 iPad 4th genetation is nearing 10-years old.
Batteries do not last forever.
The internal battery in that nearly 10-year old iPad may be failing after all of these years.
The internal, rechargeable batteries in these old iPads are running on borrowed time.
Not worth the costs to replace these old internal, rechargeable batteries in these old iPads, any longer, either.
No trade-in value for such old iPads, either.
Sorry.
Apple ended support for all 9-11-year old iOS devices nearly 5 years, ago, in 2016.
Third party app developers abandoned and stopped supporting these 8-10-year old iOS devices nearly 3 years, ago, in 2018.
There are, virtually, NO MORE third party apps available from the iOS App Store, any longer!
Third party compatible apps for such old devices are few and far between, now, in 2022.
This includes apps for both iOS 9 AND iOS 10 devices and, throughout 2022, ALL iOS 12 ONLY devices!
AND, NO WAY to, initially, install any older, compatible, third party apps into this old iPad, any longer!
NO MORE SUPPORT! NO MORE APPS!
All 2011-2012 iPad 2, 3, 4 and 1st gen iPad Mini models are fully and completely unsupported AND obsolete!
Sorry, but this is the reality for ALL 9-11-year old AND OLDER iOS devices now. Especially now, in 2022.
May br time for you to really need to seriously consider a purchase of a new iPad model OR a much, MUCH “newer” and less expensive, refurbished or used iPad models, from better known, trusted Apple product/device retailers/resellers, some locally or from online, on the Web/Internet, capable of running the latest iPadOS versions.
There are PLENTY of less expensive, newer, older iPad models that can run the latest, current versions of iPadOS.
If you need OR ONLY able to purchase older, less expensive iPad models, look at older iPads from 2014 and later.
All of these older model iPads below, CAN, currently, run the latest releases of iPadOS 15.
2014, 9,7 inch screen iPad Air 2 models ( NO Pencil support )
2015, 7.9 inch screen iPad Mini 4 models ( NO Pencil support )
2015-2017, 12.9 inch screen iPad Pro models. ( 1st gen Pencil support )
2016, 9.7 inch screen iPad Pro models ( 1st gen Pencil support )
2017,10.5 inch screen iPad iPad Pro models ( 1st gen Pencil support )
2017, 9.7 inch screen iPad 5th gen models ( NO Pencil support )
2018, 9.7 inch screen iPad 6th gen models ( 1st gen Pencil support )
2019, 10.2 inch screen iPad 7th gen models ( 1st gen Pencil support )
2020, 10.2 inch screen iPad 8th gen models. ( 1st gen Pencil support )
2019, 7.9 inch screen iPad Mini 5th gen models ( 1st gen Pencil support )
Get the largest internal data storage model you can afford as NO Apple iOS device has ANY expandable storage.
I am sorry that you had to learn all of this, but this does not change any of the facts regarding these very old iOS devices.
Please recycle these old devices properly and responsibly.
Sorry & Best of Luck to You!