You're gonna need a bigger boat.
The configuration you have would be great to modulate your other equipment, but not so good as a standalone instrument (IMO).
If you want something all-around that you can use stand-alone or with your other equipment, check out the Andrew Huang starter system. It's a great balance of modulation, sound generation and effects to explore.
https://www.perfectcircuit.com/andrew-huang-system.html
You could use Andrew's as a starting point and maybe swap out Plaits for your BIA. That'd give you an extra 2hp, I'd swap out MCO for Klavis Twin Waves to build a basic subtractive synth voice (check the depth will fit).
Marbles is awesome, but large for such a small case. Maybe look at a smaller Marbles clone, or Qu-Bit Nano-Rand.
I might go here with it:
https://cdn.modulargrid.net/img/racks/modulargrid_1260559.jpg
Just my 2c. Modular is a very personal exploration. Enjoy your leap!