Thank you so much for this hint.
Looking closer at what seemed a bit complicated, I rememberd that I already have a PlugIn that loads VST3 PlugIns. It is called nektarine and came with my Nektar Panorama Controller.
And despite working fine with other VST3s, it does not with the Band in an Box DAW PlugIn.

In short, the VST3 behaves as the VST2 does (no sound unless the generated files are dropped into the DAW), but it does emit chirps and beeps of high frequency when running whereas the VST2 is silent.
So I guess that it would do the same with Element and I am back to square 1.

Until this might get fixed sometime in the not so far future, I am fine with my workaround (using the Standalone Version to generate and check the files, then drop them into the DAW when satisfied; sync play is not so important at least for now)

Having that said, this Element software seems worth exploring.
Thank you again to let me know.
“Musicians”: Band in a Box UltraPak 2020 - 64 Bit
DAW: Reason 11 Suite - 64 Bit
Notation: MuseScore 3
Audio Interface: NI Komplete Audio 6
Microphone: RØde NT1-A
MIDI Controller: Nektar Panorama 6
OS: Windows 10 64 Bit