From our experience, Tersus is very useful for such applications, and a single person can achieve very high productivity, especially if you need applications used both from the desktop and from mobile devices.
It would be difficult to assess, though, how your productivity will be compared to .NET and C++, because this depends greatly on your level of expertise with these languages, the libraries and templates you have in order to reuse components between applications, and, of course, the specific nature of the applications you develop.
I guess the safest would be to devote a couple of days to learn Tersus and create a POC (some small application that resembles the applications you have in mind). It won't prove anything, but probably give you a good feeling whether you are on the right path.
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