It depends on the needs of your own music, really.

For me, a “song” played back live is me jamming on 4 patterns per Elektron machine with lots of realtime tweaking and variations, and loads of kit/sound/pattern reloads to bring things back around. My kits are titled based on the patterns used i.e. Kit 1 = A1-A4, Kit 3 = A9-A12
This gives me 32 live “songs” , and 32 kits per Project (AR & A4).

But I make techno, so it works for me. I would rarely need to switch between Projects but will eventually as I make more and more material for live performance with Elektrons.

So I’ve started to engineer a solution for the future, and I’ve come to the conclusion of having an Elektron box with a track dedicated for bridging material while another box loads a fresh project.
For instance, 1 track on the Analog Four that’s a fairly interesting drum loop that I can go crazy on while the Analog Rytm loads a fresh project. Fortunately, any Elektron box will do the job thanks to sound/parameter locks. To get them all back in sync, I can do a big FX tail wash / dubbed out delay feedback thing with the seqs all stopped.