Useable? Perhaps, but useably and utility is likely to be significantly influenced by the availability of Apps that remain compatible with your iPad.
The first generation iPad Air, iPad mini2 and mini3 can only be updated to iOS 12.5.7. These models are effectively obsolete.
Apple ended major update support for these models of iPad in September 2019 - although they have continued to receive occasional “point” security updates, the most recent being released January 2023. These devices cannot be updated to iPadOS 13 (or any later major versions of iPadOS) as the internal hardware does not meet the minimum technical requirements (CPU capabilities and available RAM) for newer versions of iOS/iPadOS.
Many App developers have dropped support for iOS versions preceding iOS 13.x for technical reasons (often because APIs or software libraries upon which they rely have been updated in the new version of iPadOS, making their App incompatible with earlier versions).
Whilst some App titles remain compatible with your iPad, if you want or need to access to Apps requiring the most recent versions of iOS, you’ll need to consider replacement of your iPad with a much newer or current model that supports iPadOS 17.