Use
ffmpeg -i "!original!" \
-map 0:v \
-map 0:a \
-c:v libx265 \
-preset medium \
-crf 28 \
-c:a copy \
"g:\Prepare\Convert\!file!"
FFmpeg by default only picks one video, audio and subtitle track (if they are present) from among the sources. Express map assignments are required in order to include other streams. 0:a selects all audio streams.
