I see you are still running High Sierra on your MacBook Pro. The newest versions of Office requires the latest 2 versions of Mac OS.
I suspect the full answer to your issue will require a lot of information we are missing. In general Apple's systems are based upon you running new software and hardware that will support it. For example, your reference to 32 bit applications is usually an issue encountered by somebody trying to install really old software on a computer running Catalina or newer. You seem to be in the opposite situation which means parts of what you post do not seem to relate to other parts.
32-bit app compatibility with macOS High Sierra 10.13.4 and later - Apple Support