Except for the battery, which isn’t that easy to replace on an iPad. And apps relying on anything online (including browsers) stop functioning at some point, because you can’t replace the OS or install arbitrary apps.
https://www.ifixit.com/Guide/iPad+Air+5th+Generation+Battery...
(Having said that, I'm not ruling out replacing it, but I don't think I'll be inclined to do that until they stop updating its version of iPadOS.)