Battery Replacement Options

I have an old Ipad pro (11inch, 2nd gen) that I took to Apple to get the battery replaced. They told me the battery was at 88% (the IFixIt app said it was at 79%). They said they couldn't do anything and send me on my way after trying to upsell me on a new Air.

So, am I better off using a third-party replacement or waiting until Apple finds it bad enough? Are Apple's batteries better enough to wait?