To use TDS projects you need to install the Visual Studio plugin.
the TDS 184.108.40.206 you use is a recent version this should work. have you try to restart Visual studio and try to load the project again?
Download TDS classic and arrange a license. there is a FREE Trial (30 days)
For Sitecore 10, there is also the option to use Sitecore for Visual Studio or the free command line tool CLI. so what you are going to do, learning is still relevant for existing Sitecore 9 projects, but with upgrades to 10 new tools are available.