I have uploaded a wip version of ibus-typing-booster to this PPA:
https://launchpad.net/~gunnarhj/+archive/ubuntu/ibus-typing-booster
I installed it and played around a bit, and it seems to do its job well. I will probably propose it for Debian, but it would be great if a few users could test and provide feedback.
P.S. Don’t install that package on an earlier Ubuntu version than 20.04. I don’t think that would work.