Hier noch aus einem älteren Thread die Info, wie man zwei XCode-Versionen parallel betreibt:
1. Download
https://download.developer.apple.com...Xcode_11.7.xip
2. Extract the xip file using Apple's archive utility in your downloads folder. (a xip file is a codesigned zip file unique to Apple)
3. When this has extracted, rename the Xcode
package to say Xcode11.7.
4. Drag this over to your Applications folder. Because it has been renamed, it won't overwrite your existing Xcode installation.
5. Launch either version of Xcode.
6. Open Xcode | Preferences and select Location.
7. In this screen there is a command line tools dropdown. Select Xcode 11.7.
8. Back in Delphi, try to add a new macOS
SDK. This time you should get an option to add 11.5.