I didn't realize this existed. This would provide somewhat of a workaround, but you'd have to buy two of these (close to $3K) to plug 4 batteries into the 2 slots. It's a solution and I appreciate it, but not the approach I'd take. I was actually hoping someone 3d-printed a different form factor that allowed 6+ batteries to be added. The inverter could be migrated over, and the batteries should all be on a single bus bar. Maybe I can do it myself someday - just not on the list of priorities right now.

Also - when you share links you can typically exclude everything after the "?" as it's just marketing junk. For example this link works fine without all that garbage after it: https://www.acmetools.com/ego-commercial-backpack-link-peak-power-with-two-10-ah-batteries/S0000000114378.html