You may need to define “working poorly”.
Your first generation iPad Air can only be updated to iOS 12.5.5 - and this, in part, may account for some difficulties that you may experience. For example, some Apps may now require a higher version of iOS than your iPad can support. A similar situation will exist for your Mac computer.
Apple ended major update support for the iPad Air1 in September 2019 - although it continues to receive occasional “point” security updates - the most recent being released late last year. The Air1 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 and RAM) for newer versions of iOS/iPadOS.
Some 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 many 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 newer or current model that supports iPadOS15.
Sorry, I appreciate that this may not be what you were hoping to learn.
I hope this information provides clarity as to your available options - and the fundamental limitations of your iPad.