For Q2: I would recommend your native layout. I’ve not tried US QWERTY but I tried DVORAK many moons ago because it’s “better”, but I found it’s better to be good at one layout than to try split your efforts. If you’re not doing something where speed is crucial, just use what you’re used to. If your keyboard layout is not good for your purposes (e.g. typing a character you need often for the programming language you’re using, is difficult on your layout), you could remap individual characters or maybe there’s a layout similar to your native one but better for programming. But no need to use US QWERTY specifically. Also as another commenter said, typing speed isn’t that crucial for programming. I find I’m always limited by thinking speed, not typing speed.