One of the best aspects of Delphi is how quickly you can whip together simple GUI applications. The main issue nowadays is finding helpful resources on the internet, as hardly anybody writes Delphi anymore. For the interested, a free Delphi IDE exists (comes with FreePascal compiler): https://www.lazarus-ide.org/
Asking as someone who last saw Delphi in computer class at school, what would be the modern equivalent? Something that lets me draw a window with two number fields and a button that says "return sum", but it's two minutes of work and self-explanatory.
Tcl/Tk would be the most straightforward choice. Even easier than Lazarus. It's not really a native look, but practically nothing is truly native these days.