A keyboard layout is any specific physical, visual or functional arrangement of the keys, legends, or key-meaning associations (respectively) of a computer keyboard, mobile phone, or other computer-controlled typographic keyboard.
The German layout (aka T1) may work for monolingual Germans, who have never tried (and will never try) programming. For a Russian-born trilingual software developer, it is an abomination. The parentheses are shifted from where they are on the US, UK, and Russian keyboards. Turns out, it's a common thing in European layouts. The square and angle brackets are hard to reach. Same with the backslash, tilde, vertical bar, and even the "@" sign.
In order not to make my life miserable by either giving up on square brackets or not being able to type umlauts in a non-awkward way, I have developed the DeUs-Layout. It is my attempt to cross the US Layout with the German characters. I have remapped some keys to output European sign when pressed with Alt/Option. Those include: Umlauts, Eszett, Euro sign, and German "smart" quotes. I have also fixed ô not being present on the keyboard.
2022-08-22 totoroot has told me about EurKEY. It seems way better: It has most other European characters, which will be useful for learning French. It also has all variations of smart quotes. The "dead" keys for the accents are present too.
I will definitely try this and come back with the results. I'll have to re-learn typing the quotes and the Euro sign, but it shouldn't be too hard. Luckily enough, the keyboard is rather German-centric and puts umlauts on AOU (rather than Scandinavian or French counterparts).