if the above don't work, try
apt purge libopenmpi.
Don't forget the period !!!Then do
apt autoremove
and
apt update; apt install -fy
Any errors post them, if it's like your other
post, I for one won't respond
Why you are still getting this error means you don't do a full-upgrade often enough.
If you want to continue using siduction (sid), you must full-upgrade often, at least once a week, 2 weeks tops, your errors are old and have been fixed awhile ago.
Hint: Stop using synaptic in sid, it will break your system sooner or later.