I am assuming you are talking about the Zoom Meeting application.
I ran the command
strace -o debug.txt -e trace=file -f ./ZoomLauncher
This showed at one point to run libibusplatforminputcontextplugin.so which is part of the zoom package. To guess what is happening without a full deep dive into the product I ran:
strings ./platforminputcontexts/libibusplatforminputcontextplugin.so | grep -i ibus
This showed that there are several strings that reference ibus. So the application likely needs it.
The easier solutions are not using gnome variant or trying to run the application in wine.
If you want to directly want to stop it you could try to stop the changes from happening. I am not running Cinnanmon so I am guessing at the solution so you may need more research. The debug file from earlier can show all files accessed. Running the following can show a cleaned up list of file accesses.
cat debug.txt | grep -v "No such file or directory\|RDONLY\|exited\|unfinished\|\"/dev/" | grep "[0-9]* openat("
Zoom seemed interested in my "/run/user/1000/dconf/user" file. To be clear (due to recent events in the news) I am not saying this malicious I am saying on my system the modify time changed the same time as when I was running zoom. My lack of statement is due to my current knowledge of dconf is low and from what I know there are many legitimate reasons to change a field in this field for any friendly application. If it is modifying dconf settings there could be something in there that is starting ibus. If that is the solution the I would recommend changing permissions on that file to not allow your user to change it.
chmod 400 /run/user/1000/dconf/user
or the dconf file under your home directory if zoom is modifying it. This very possibly can cause poor and unexpected behavior, but the question tone seems to indicate that this would be acceptable. There are also options for locking dconf with the same caveats. Locking dconf