In case there is no particular reason for it, I would use the latest openLCA1 version 1.11.0 or maybe even the development version of openLCA2. In the latest versions for openLCA1 and openLCA2 the RAM allocation (increasing RAM) on MacOS is possible by simply using the File/Settings menu inside the application.
In case you want to manually change it in the openLCA.ini, I can tell you that MacOS sometimes hides a package "folder" as a "file" inside its application files. Just right-click on Contents (which you found as a "file" inside the openLCA.app folders) and select again "show package contents".
Step-by-step: right-click openLCA.app "show package contents", right-click Contents "show package contents", change the openLCA.ini.
In newer openLCA versions, you will find the RAM allocation in the folders Contents/Eclipse/eclipse.ini but for newer versions you can change it anyway much faster/easier in the app settings menu.
Best wishes, Conrad