The username is EarnestAl not EarnestAI; the font used here may confuse the characters l (lower case ell) and I (upper case eye) to an unsuspecting eye.
Please appreciate that we may not be experts in MacOS, but are using web searches to try and provide some pointers for you. You could of course try some research on MacOS settings for yourself.
In LibreOffice the Recent Documents list is in File > Recent Documents, or in the Start Centre.
Other recent document lists in the Dock or Task Bar (Windows) are compiled by the operating system; look for settings in the OS.
Maybe this helps, although the limit is defined by time rather than quantity, How to Add a Recent Items Folder to Your Mac's Dock - MacRumors