Is the iPad 2nd generation still usable if I reset it?

The iPad2, iPad3 and iPad mini1 can only be updated to iOS 9.3.5 (WiFi Only models) or iOS 9.3.6 (WiFi & Cellular models).

Apple ended update support for these models in September 2016. These models of iPad cannot be updated to iOS 10 or later major versions of iOS, as the internal hardware does not meet the minimum technical requirements for new versions of iOS/iPadOS. This limitation cannot be bypassed; these are 32-bit architecture devices, whilst all recent versions of iOS/iPadOS are designed for 64-bit hardware platforms. iPad2, iPad3 and iPad mini1 are fully obsolete.

You need to consider that compatible Apps for older models of iPad are no longer available - as App Developers have dropped all support for 32-bit devices. As older versions of Apps are removed from the Apple App Store, you’ll not be able to (re)download or install them - which may severely limit the usefulness and utility of your iPad.

Also understand that, for security, Financial Institutions and other commercial websites often require that customers use computers that are both using a current/supported version of the computer's host Operating System - and secure version of web browser software. If your iPad (or other computer) cannot meet the required minimum requirements, you have no alternative than to replace the computer with a device and OS that does meet the required minima. For iPad, if you need to access to Apps requiring the most recent versions of iOS, you’ll need to consider replacement of your iPad with a newer or current model that supports iPadOS 17.

The iPad 2 has a 32-bit processor, and can't run anything higher than iOS 9.3.5.

Apple moved to 64-bit processors and apps a long time ago, so I'm not sure whether your iPad would even be able to access the App Store today. If it could, there might be few or no apps there that would run on it.