Found the answer - VLC can not playback audio in RARs which are RAR version 5, only RAR V4.
Solution add "-ma4" additional parameter when making RARs with 64 bit app "Better Zip"
We routinely used Simply RAR to create .RAR files from .WAV files under Mac OS Mojave, and older (32 bit) OSs. with no compression. We could then open those RAR files with VLC, and play back the audio without the need to decompress the files When we moved to Catalina, and other 64Bit OSs, Simply RAR...