A 2nd gen iPad cannot be upgraded beyond iOS 9..3.5 for WiFI ONLY models/9.3.6 for WiFi & cellular data models.
A 2nd gen iPad is an OVER 9-year old device, now!
There is, virtually, NO MORE third party app support, any longer, for these 8, 9 and 10-year old iPad models, any longer.
These old 8 and 9-year old iPad models are too old, now, too underpowered and completely incompatible with any of the current and future versions of iOS/iPadOS.
Sorry, but it is what it is, today, in the year 2020!
This is the reality for these 8 and 9-year old iPad models, now, in 2020!
Apple supports new iPad models for up to 5-6 years, with third party app developers supporting these iPads for another, additional 2-3 years after!
So, that is a total of between 7-9 years of iPad/iOS support for iPad models!
ALL older iPad models, like the iPad 2, 3, 4 and 1st gen iPad Mini have, finally, reached this support limit!
ALL 8 and 9-year old iPad will be completely OBSOLETE by the end of 2020!
User, like you, keep insisting on using older technology past its support limits.
A LOT has happened with iPad in the past over 9-years and in the last 4 years since the last major update of iOS 9!
If you need an iPad that can run the latest and greatest versions of iOS, as well as, the most current apps available, then, you need to purchase a new iPad from Apple or a discounted, refurbished iPad from Apple’s Refurbished & Clearance section of Apple’s Website or a new or refurbished iPad from an Apple authorised, third party retail or online reseller OR other trusted sources for new or used Apple products.
If you decide to purchase another iPad and must purchase older, used iPad models, DO NOT look at anything older than a 2014 iPad Air 2 or 2015 iPad Mini 4.
Both of these models are the oldest iPad models that the up and coming iPadOS 14 will support, in the Fall of 2020.
If you must purchased used devices from unknown, untrusted sources, you must ask A WHOLE LOT more questions of the iOS device seller, ask for more photo/images, ask if the iPad has user/iCloud activation lock and ask for photos/images/short video proof, ANY REAL, UNQUESTIONABLE, UNMISTAKEABLE, CONFIRMED VISUAL PROOF, that such an iPad has been reset to factory settings and shown proof of the iOS device's start up screen showing the animated, moving, multi-language “Hello! Welcome to iPad” screen.
If the iOS device seller is unwilling to do all of this to show you that the iPad, in question, is ready to use with no barriers to new user activation and use, pass on the iOS device and look at other iOS device sellers, elsewhere, who will be more accommodating to answering questions and providing visual image or video proof of a proper factory reset iPad.
Sorry, but it is what it is!
Best of Luck to You!
Be Well!...Stay Well!