<a> cannot load the OLE 2.0 or Docfile libraries.

Microsoft ended support and retired Office 2019 for Mac on Oct 10, 2023.

If it were installed on Catalina before macOS Monterey was first released, then it would still work, and after Monterey was released, it would cease receiving product updates but should continue to work. New installations of Office 2019 for Mac were blocked once Catalina support was dropped by Microsoft in Fall 2022.

Just to fil in...

Look into the Free LibreOffice, it handles MS Office files like Word & Excel, & Page Layout…

https://www.libreoffice.org/

Thanks to Matti Haveri…

MS Office for Mac Mini - Apple Community

LibreOffice 4.0.6.2_MacOS_PPC works in OS X 10.5.8 (last official PowerPC version).

LibreOffice 4.3.7.2_MacOS_x86.dmg (and x86-64?) works in OS X 10.6.

LibreOffice 7.0.4 works in macOS 10.11 and 10.14.

https://downloadarchive.documentfoundation.org/libreoffice/old/

Thanks to Servant to Cats…

LibreOffice is up to

• Version 7.5.4 – Requires Mojave or later
• Version 7.4.7 – Requires High Sierra or later
• The LibreOffice site is now offering
• Version 7.6.2 – Requires Catalina or later
• Version 7.5.7 – Requires Mojave or later

Release notes indicate that as of August 2023, new versions of LibreOffice will likely require Catalina or later.

Your version of Word and macOS are not compatible. You don't mention what version of either you are running. Please include those details.

FWIW, I haven't checked the requirements but you might want to see if the free online version of Microsoft 365 works.

https://www.microsoft365.com/

Microsoft supports the three current versions of macOS. I believe Catalina is too old for Word 2019. You could use an alternative such as LibreOffice.

You may have had Office 2019 for Mac previously installed on Catalina and upgraded to Sonoma, but I would be surprised if you can perform a new installation of 2019 on Sonoma, and mildly surprised that you received as new an update as 16.78 for Word for that older Office suite.

Welcome.

Just an FYI, I have Office 2019 funning perfectly on Sonoma:

This is Word 2019