Configure a long press to kill your screensaver, open PowerPoint, and disable the trackpad.

If the mkey tool you found is outdated, consider these modern alternatives:

The canonical repository you will find when searching is often located under usernames like jergus or linux-apps . As of the latest indexing, the primary repository focuses on a lightweight daemon that captures the M-key (typically KEY_MICMUTE or a vendor-specific scan code) and allows the user to map it to any shell command.