I don't see any screen tearing on X11, with cinnamon on archlinux, on a 4K monitor, with Nvidia. No tearing when dragging windows around, scrolling text, playing fullscreen games at 4K (both native and with steam proton) or watching video at 4K. This without doing any special configuration, as far as I remember.

As for font scaling, I just choose a big enough font or default zoom level in the browsers, VTE's and text editors I use, looks perfect.