How can I resolve 'The application “OpenOffice.app” can’t be opened' error on Mac?

Try it. It seems old OpenOffice is jut not compatible with the current macOS.

OpenOffice doesn’t seem to have recent macOS support:

LibreOffice positions itself as the successor to OpenOffice, and was forked from OpenOffice many years ago:

LibreOffice is a powerful, free and private office suite - the successor project to OpenOffice - used by millions of people around the world. It's compatible with Microsoft Office (365) and is backed by a non-profit organisation, The Document Foundation. LibreOffice includes Writer (word processing), Calc (spreadsheets), Impress (presentations), Draw (vector graphics and flowcharts), Base (databases), and Math (formula editing).

Here are the LibreOffice supported file formats: https://en.wikipedia.org/wiki/LibreOffice#Supported_file_formats

Switch to LibreOffice.

https://www.libreoffice.org/

https://wiki.documentfoundation.org/Documentation/System_Requirements