Just a suggestion:
Go to /etc/environment.d
Create a file called ibus-custom.conf
Add these two lines:
unset GTK_IM_MODULE
unset QT_IM_MODULE
Now these enviornment variables should be unset every time the OS boots up.
If that doesn’t work you could try adding these lines to /etc/bash.bashrc file and start a bash shell on startup immediately.
Make sure to backup those files so you could easily restore them if anything goes wrong.