I don't recall this being a problem before BIAB 2019 -- it didn't affect my install anyway. Version 604 installed.

Now -- if you go to "MIDI Driver Wizard" tab in the audio control setup dialog box:
There are 2 choices with radio selection buttons.
"internal Speakers"
"External Speakers (via indicated MIDI connection, another button)"

If you select the SECOND ("External") and then the MIDI device this holds at times, but upon restart of the program it reverts as default to the FIRST ("internal") which typically uses MS Wavetable. Also seems to go back and forth under some MIDI driver changes.

Prior to 2019 I had no such difficulty. I use ASIO drivers.

This appears the case in either the 32 or 64 bit versions.