This is not true. In 2020-2021 curriculum year in Ukraine there were 874 schools that that had languages of minorities as a language of instruction. In 9 different languages - Russian, Bulgarian, Crimean Tatar language, German, Polish, Slovak, Hungarian, Romanian, Moldavian.

Source, official website of Ministry of Education of Ukraine. (in Ukrainian) https://nus.org.ua/news/mon-pidrahuvalo-skilky-shkil-navchay...