I'm thinking about purchasing a refurbished Macbook Air 13.3inch with 128GB SSD and 8GB RAM for developing an iOS port of my famous "Cat Litter Reminder" app..
It has MacOS Monterey on it which according to this can target iOS up to version 16.2.
My question is: does this make much difference? Or is it important to be able to target the latest version?
Starting April 29 Apple is going to require Xcode 15 for App Store submissions. Xcode 15 requires macOS 13+.
https://developer.apple.com/news/?id=fxu2qp7b
The chances are high you won't be able to submit apps with that MacBook Air.
I recommend buying a Mac with an ARM processor. ARM Macs are going to be supported longer than Intel Macs.