Ask the app vendor; the OpenOffice Mac developers Over at Apache. Or you’re undoubtedly welcome to help with the app.
The current OpenOffice version specs list support for OS X 10.7 through macOS 10.13. Not for 10.14 and later. Whether that’s an error?
It appears there are some 32-bit issues still lurking with the OpenOffice Catalina testing. Log the bugs that you find. The 64-bit app migration has been underway for all app developers since around OS X 10.4, and with 32-bit app problems flagged to end-users starting with macOS 10.13.4.
Your choices here are limited to waiting for OpenOffice updates, reverting to or otherwise running an older macOS version, running macOS as a guest in a virtual machine and OpenOffice running within that guest, or migrating to alternatives including LibreOffice, and Microsoft Office, or using the Apple iWork apps. Apple iWork can read and write various Office documents, but does not support all Office features.