You can try using LibreOffice.
You can also try using the Apple's Pages app, but this may not be an option if you never installed it previously for Catalina.
I think if you have a MS subscription to their cloud based Office, it may be possible to download a version of Word compatible with Catalina....although it will be an older version. I just saw this option while trying to reinstall Office on an upgraded Mac with my employer's Office subscription....not sure if that is an option for everyone, best to check & confirm with Microsoft before purchasing since Catalina is no longer a supported OS for MS.
FYI, if a file was created or modified by someone using a newer version of Office & they used a feature only available in a later version, then it would require you to use the same or newer version of Office. LibreOffice may be handle it. If these were files you used yourself with older versions of Office, then they should open just fine on any later version of Office. IIRC, the 2007 Office/Word file formats are still supported.
Maybe the problem is not compatibility, but a macOS issue with opening or accessing the files. What is the exact error message you receive when trying to open these files?