How old can I go to be able to build an iOS app?

I am developing an Android/iOS app in Flutter. I am currently using VS Code on my windows to create the app and it's working fine on the android side but I am facing an issue with iOS as I don't own a Mac

If I understand things correctly, I will need a Ventura OS environment to build and publish my app on the App Store. I know I could rent for a time a virtual machine but I'd rather have a physical one. Problem is, I don't want to spend several hundreds or thousands of bucks on a MacBook.

I was thinking of buying an older Mac (16GB RAM and 500GB SSD) and install a Ventura OS on it using OpenCore Legacy Patcher. If follow this list of supported versions, I can use a MacBook from up to 2008, even if I don't think it would work as needed.

How old can I go to be able to use a Mac just to build and publish an app?

Thanks in advance!