How to Build an Application compatible with older MacOS with Xcode?
I am not sure if this still works on Mojave, but there is a project called XcodeLegacy which is created specifically with this intention in mind:https://github.com/devernay/xcodelegacy
Regarding the menu, you can find it at: Xcode -> Select File -> Project/Workspace Setting
Works on Xcode 13, I'm a bit late to the party but just had the very same question.