I was afraid everyone would interpret the theme the same way I did. But in the end we have so many different games!
The executable is small because I don't use game engines. Instead I use C and some libraries (raylib in this case). This approach is not that popular these days (because of game engine propaganda xD). But actually it saves time! Instead of fighting the engine to get what I want I can just write the code. "In the beginning you always want results, in the end all you want is control" (c) Eskil Steenberg
I don't have a 4K monitor to test this but I think your problem is related to vsync.