As Mario mentions, BIAB's 'built-in' MIDI player is not great and it's well worth getting another. Curiously IMHO, PGM have quite a good engine 'hidden away' in a subfolder. It's VSTSynthFont and you'll find it in the PGM manual.

It comes with a passable soundfont, but there are other, better, soundfonts available free. I personally use mostly Compifont and "Timbres of Heaven". YMMV. Searching for "free sound fonts" may help.

There are also the bigger engines like Native Instruments' Kontakt.

With a user-played melody track, these can often sound quite good just as one recorded them, but as Mario points out, judicious use of MIDI CC command (continuous controller) can make a big difference, especially with some of the smarted sound engines. Those like the SWAM engines are amazing if costly, as are the Spitfire Audio tools for some things. There are lots of options. Small steps.

Jazz relative beginner, starting at a much older age than was helpful.
AVL:MXE Linux; Windows 11
BIAB2025 Audiophile, a bunch of other software.
Kawai MP6, Ui24R, Focusrite Saffire Pro40 and Scarletts
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