I got to this issue by becoming aware that MacOS's time machine is backing up large amounts of data (say usually 1-3GB for each backup, i.e., each hour) while I am not doing anything on the computer. Now, I know this can happen occasionally but this has been happening regularly for weeks now. I'm wondering what files and folders are being changed and subsequently want to find out by which process.
So how can one find folders or files in the filesystem that are subject to most "traffic" within a period of time (1 day or so), i.e., files where much of the content is changed or folders where much of the files within are changed? These should be sorted by the number of changes (in bytes) per file or folder.