Live rack module suggestions

I am a noob to eurorack. My first intro to eurorack was at NAMM 2020 where I walked through the modular section and was amazed at the possibilities that modular can bring. Since then I've mostly done research on live performances using modular racks and this is what my focus is.

After some research, I'm pretty confident about buying a BeatStep Pro to sequence my modular and to control a Volca Sample 2 for drums and samples. This leaves me with 2 sequencers on the BeatStep Pro to sequence my modular. I'm not so interested in buying a mother 32 or 0-coast as a starting point. I'd much rather start buying modules.

As far as a case I'm either getting a Mantis or some sort of DIY rackmount hybrid case, but I'm leaning towards just getting a Mantis.

I'm looking for advice on performance-oriented modules for a basic but expandable rack. I have tons of experience soldering so I'd rather buy DIY kits even if it only saves a little cash.

Don't settle on that BSP just yet...have you checked out the Keystep Pro? Imagine two BSPs jammed into the same case with a velocity-sensitive keyboard, user-programmable arpeggiator, dual expression controllers, loads of I/O. And just $140 more.

Even with two BSPs and a Keystep on hand here, that KSP is something else! And I can lock all of that crap up to most anything, since it all plays nice with +5V clocking. It's a decent size-fit for a 104 hp cab, too.