qwerty42 with an AltGr key for each side #2
Description
This is a cool project! I also have a one-dead-key concept on my keyboard layout (implemented in Firmware, because I also wanted a navigation layer: https://medium.com/@willitheowl/key-mapping-lessons-learned-from-one-year-with-the-ergodox-and-iris-bf5f64a28ad8 & https://github.com/matey-jack/qmk_userspace_iris_cozy_keymap.)
But your qwerty42 is even more interesting, since with all the programmer's punctuation moved to the AltGr layer, I can keep my German letters on the main layer. https://github.com/matey-jack/keyboard-layer3
I see you put the important punctuation on the side opposite the AltGr key, which is very smart! But then you also mapped a lot of extra things on the right-hand AltGr layer. Have you thought of adding an AltGr on the other side of the keyboard? Especially since the ISO <> key is now available for that? My layer3 project linked above has the configuration files for this at the bottom of the Readme. (Documented in German, but needs no words to understand. ;-)