I’m not sure if this is useful for people but I thought I would share it just in case or maybe someone knows a better approach.
MacOS 10.15 (Catalina) from what I understand does not support 32-bit applications. The following relevance identifies running processes that are 32-bit:
pathnames of image files of processes whose ((((it is 7) of (byte 7 of it + byte 4 of it) of (file it))) of (pathname of image files of it))
Live long and prosper,