Arch also kinda allows that if you write custom PKGBUILD file. It’s easy to write for simple stuffs that are based on make/cargo etc.

It’s time consuming if some program gives you 100s of lines of code in bash script to install their program though.

Edit:

Another disadvantage of building from source is dependency management. You might accidentally uninstall some dependencies, the standard library versions might change and break your packages, etc.

Can’t you just keybind the switch to that key? I use arch and I have keyboard layout switch between three languages (one is Japanese which might have similar tech/typing style), and the program I use (ibus anthy) allows me to define my keybind.