If you attempt to run a 64-bit VSTO add-in without the x64 runtime, you will typically see an error like:
The "2010" in the name refers to the version of the tools, not strictly the version of Office it supports. Interestingly, this runtime supports Office 2007, Office 2010, Office 2013, Office 2016, Office 2019, and even Microsoft 365 (formerly Office 365), provided the appropriate version of .NET Framework is present. microsoft visual studio 2010 tools for office runtime -x64-
If you are still depending on the 2010 runtime, evaluate these paths: If you attempt to run a 64-bit VSTO