Getting closer: I tried the compiled st in different window managers (thanks for the hint to test the binary in different environments!).
In Plasma, spectrwm, and dwm, UTF-8 of st does not work. But SURPRISE: in Gnome (Wayland, PoP OS! 22.04 LTS), it does! This means that the compiled st is working fine, but something strange is happening related to the environment. But what? Anyone has an idea, what could be the difference between Gnome and DWM with respect to the font encoding?
