Microsoft provides several alternatives and migration paths for developers and users:
The modern Office ecosystem has moved on. The VSTO 2010 runtime was not designed for the "Click-to-Run" architecture of modern Microsoft 365. Users trying to run old VSTO 2010 solutions on new builds of Outlook, Excel, or Word are experiencing random crashes, load failures, and disabled add-ins. visual studio 2010 tools for office runtime end of life