Didn’t they actually ask to be reunited with Russia at one point?
I don’t know what the people of Belarus want, but the political leadership apparently has been very pro-Russian. Lukashenko has been in power since 1994 and from what I have read runs the country in an authoritarian way...so not much has changed since Soviet times apart from not having to spout Marxist-Leninist rhetoric. Both the Belarusian and Russian languages are official...the Belarusian language is close enough to Russian that some consider it a dialect of Russian. (Its version of the Cyrillic alphabet has two letters not used in Russian Cyrillic.)