Does it support input anyway? Can a user choose a table row with arrow keys and press a button to do something or input a value?

It's not a TUI library in that sense. You should check out Gui.cs if you want to build more interactive applications in C#: https://github.com/migueldeicaza/gui.cs

Thank you. I don't even care much about the language. I can code C#, Python, many others and don't mind to learn some new.

What I need is a library to give me high-level TUI widgets (kind of like VisualBasic for DOS, not necessarily WYSIWG - code-first is OK) which would look good.

The one you have linked seems the best I have seen (among all the languages) so far but Spectre.Console looks (literally, I mean the aesthetic aspect) even better.

Check out https://github.com/rivo/tview (golang), https://github.com/prompt-toolkit/python-prompt-toolkit (python) and https://github.com/fdehau/tui-rs (rust).

Personally I went with prompt toolkit for a work project I had to do in python and it is great!