Does ibus work seamlessly in Wayland yet? As a person who regularly needs to input French, Chinese, and Japanese, besides English, I tried Wayland in Kubuntu 20.04 and a non-working ibus was a complete showstopper for me.
1: https://cpplover.blogspot.com/2013/10/ibus-15_21.html
2: https://uwabami.junkhub.org/log/20210224p01.html#p01
3: https://uwabami.junkhub.org/log/20210312.html
4: https://lists.debian.or.jp/pipermail/debian-devel/2021-Febru...
Handling input is an integral part of what a compositor does, and it's not an easy problem to solve when said input doesn't map linearly to text.
Input methods in particular are not something that X11 "solves" at all: Under X every toolkit implemented their own way of handling complex input methods. XIM existed, but it was limited and only there for compatibility with ancient applications.
There are Wayland protocols for complex input methods too. Gnome's gone all-in and integrated ibus with their own compositor, so that obviously works, but Gnome also benefits a lot from distributions like Fedora making sure it works: everything is set up correctly out-of-the-box if you use Gnome. However, more niche implementations like Sway have to deal with a lower level of integration because there's no distribution that's built around Sway to create a full desktop environment.
In my case, I wanted to keep my configured xkb keyboard layouts + I wanted to be able to use ibus in parallel for CJK.
Ok, there must be a problem with *my* KDE setup: when I try to disable KDE keyboard layouts, KDE does not persist changes to the next session: when I log in next time, KDE keyboard layouts are enabled again and interfere with ibus.