And yet, QT picked JS for the language of its state of the art widget library.

Not to mention a lot of QT apps bundle the entire thing as well, so I have in my PC several versions of qt5win.dll and friends, many exactly the same.

Furthermore QT apps are not a guarantee of fast programs, and often the interfaces look horrible.

I fail to see a huge difference in programming methods, even if the QT runtime clocks at about 50mb instead of 500mb.

But just for the GUI. The rest of your QT application could be written in highly tuned assembler, if you wanted to go that route…

Qt apps break all the way to being unusable on my windows system when plugging in an external display or RDPing to the machine. I use Kleopatra, Electrum, Qbittorrent, VLC, they all have scaling issues where the text and icons does not scale correctly with the buttons and other components.

Is your external display a much higher dpi than your built in screen and are we basically talking about desktop OS being shitty about handling mixed dpi?

External display has a lower dpi. I don't know if it's the OS or something else but it only happens with QT apps which makes me avoid them if possible.

Here is an example: https://imgur.com/a/RZZK7nA

This is a valid opinion but a bit extreme as is. If the competitor lacks some features that would save you days vs a few minute of execution, you are trading your limited CPU, memory, and bandwith for your (unlimited?) own time.