Your iPad Mini 4 is too far behind in iOS upgrades/updates.
If you have access to a full computer, like a Mac or Windows PC, try either using the Finder on a Mac that has the newest macOS Catalina installed OR with an older Mac with an older Mac OS, download and install the latest iTunes version ( or latest iTunes for Windows PC ), make sure the Mac or Windows PC is connected to the Internet, connect your iPad by the USB charge cable to the computer and let the iTunes application upgrade/update that 2014 iPad Mini 4 model, using the iTunes Software Update feature, to its current, maximum iOS of iPadOS 13.5.
Good Luck!