This might signal a different story than just "badly". Estonia might flex with their 2% in this article, but as I understand their current situation – too many students fail much earlier in there. About 25% don't reach mininum level in math skills in their basic education level exams (15-year olds).
I looked into it "The gap was approximately 10% to the detriment of the Arab students in their first year of study, but decreased from year to year. This gap was found to stem primarily from language difficulties."
Haredi Jews and Russians who refuse to integrate are probably also big thing.
Why are Russians supposed to integrate? They are not Jews (if you mean Russian spouses of Jews). They are there so that their Jewish spouses are there, too. They don't "multiply" in the sense that their Israeli-born kids do not grow up Russians, so it's not like Israel is risking being "liberated" by some Putin successor someday, their culture dies with themselves.
I mean Russians Jews are not integrating. Just because you are a Jew does not mean that you share the values and culture of other Jews. Just like ethnic Russians culture as been molded by Stalinism and communism, so has Russian Jewish culture. By large they have the same backward values and are bringing them to Israel (this already shows in politics and other things).