Are Belarusian ATC recordings available for Ryanair Flight 4978?
Not every country allows recording and publishing of ATC communication. The UK for example does not: Is it illegal for Joe Public to listen to ATC in the UK?
While I don't know for sure, I'm guessing Belarus does not allow it. LiveATC has a coverage map, which shows the destination airport EYVI (Vilnius) is covered, but nothing in Belarus is:

I therefore doubt you will be able to get the recording. Since the incident is currently being investigated by multiple countries and organizations, a recording or a transcript might be available in the future as part of the investigation report.