Excuse me if i wasn't very "precise".
However try an
# emerge @downgrade
Then must be revisited the "/etc/portage/package.accept_keywords , mask, unmask & use).
# emerge -DNu world --with-bdeps=y
Be conscious that it is like a "little surgical operation" in your system.....
Sometimes is necessary to return to "core" profile then restarting versus another profile ....
Paste any errors you encounter; so to may able to give you a "little hand"
If you want i can enter in your system to take a look about errors.
And You (if You want can take a look about my system that is based on Funtoo Stable (e.g. i can post my config_files to You as example)
Hello to All