Have you ever noticed UFED Physical Analyzer not decrypting every WhatsApp database? Do you know that there is a pattern?? Try using this tool to find "lost" keys!
Pre built binary for windows: whatsapp-carver.exe Sources included. Its very easy to build in linux and windows with cygwin
Search for the very first 30 bytes in the whole mmcblk0. Take a look at the diff between a 2018 key and a 2021 key (up to encrypting crypto14 files)
.\whatsapp-carver.exe MMCBLK0.dd