Entering [ works just fine on QWERTZ: You simply press AltGr+8.
But this doesn't work in shortcuts, e.g. when combined with Ctrl. That is, AltGr+8 generates the character '[', but Ctrl+AltGr+8 is not the same as pressing Ctrl+[ on keyboards that have a dedicated [ key.
This bug is decades old, and every Vim derivative suffers from it.
I use Cmd+[ on MacOS to "go back" on multiple software like IntelliJ, emacs (I probably configured it) and Firefox, so I would say this is a pretty common combo. It's easy to remember, specially given that the mirror, "go forward", is Cmd+]. As I said, even though my first language is not English, I only write code in an English keyboard layout so I've never even considered that [ is "hard to press".
EDIT: the Dr Racket editor even lets you write Lisp using '[' and ']' because they don't require pressing shift like '(' and ')' so are easier to press.
Using [ and ] is completely normal in so many applications. QWERTZ just is a bad design, and applications shouldn’t have to work around that by making keybindings more difficult. My team has ~100 engineers in QWERTZ countries and I don’t know a single one of them that actually uses it. QWERTY is the standard order for all new laptops. Nobody complains.
All the time while reading this thread I could not remember an issue like that from the time I used Vim/NeoVim. Perhaps it somehow did not affect me? At least in Emacs that works exactly like it should.
But this doesn't work in shortcuts, e.g. when combined with Ctrl. That is, AltGr+8 generates the character '[', but Ctrl+AltGr+8 is not the same as pressing Ctrl+[ on keyboards that have a dedicated [ key.
This bug is decades old, and every Vim derivative suffers from it.