On macOS devices, I love the feature of having alternate characters shown by a long press of any key (see screenshot attached).
As I use a DVORAK US keymap on my loved Thinkpad, I do not have access to accentuate character I use in French unless I switch to AZERTY keymap.
Switching often is a bit painful and a big source of mistakes. I hope to have a similar feature in my Wayland graphical environment.
I didn’t found yet something that fits my need, and I consider implementing it with IBus, without knowing what could be a good way to start hacking on it.