2014 MacBook Pro won't update past Sierra 10.12.6

Apple uses the term "upgrade" rather than "update" when going from one major version to another.

A mid 2014 MacBook Procan be upgraded to the latest  version of Big Sur macOS 11 or earlier but no later. See: How to download and install macOS - Apple Support

Be aware that if you upgrade to Catalina 10.15 or later you will also need to update any non-Apple 32-bit apps. See: https://www.stclairsoft.com/Go64/

or

 https://www.macworld.com/article/232735/how-to-check-if-mac-software-is-32-or-64-bit.html