How to install the legacy Visual Studio extension
ReswPlus currently supports all versions of Visual Studio 2019.
In Visual Studio, select Extension > Manage Extensions, then select Online on the left, search ReswPlus and click on Install.
You can directly download the extension here: https://marketplace.visualstudio.com/items?itemName=rudyhuyn.ReswPlus, close all instances of Visual Studio and run the .vsix file. It will install the extension on Visual Studio 2019 automatically.