Are there versions of LibreOffice available for MAC OS Monterey 12.7.6? As the new one is not compatable.
Yes, there are. On Download LibreOffice | LibreOffice - Free and private office suite - Based on OpenOffice - Compatible with Microsoft, make sure that under “Choose your operating system:” you select “macOS (Intel)”. This way a file will be downloaded whose file name ends in “MacOS_x86-64.dmg”. This will work with macOS 12.7.6 Monterey.
The download page has a “System requirements” link, which should provide information about versions of operating systems supported by the versions suggested on the download page; and if your version of operating system isn’t supported by them (which will eventually happen also for macOS 12), you can always find the latest version of LibreOffice that used to support it, on the dedicated wiki page (which is linked from the bottom of the mentioned “System requirements” page).
Also: the question didn’t mention the architecture of macOS 12. The answer advised to use “Intel” (x64-86), for some reason. It may be useful to choose based on your system architecture.