Yes I do know that feature. Though with as scatterbrained as I can be these days as I get older (much older), the project feature really does come in handy helping me organize my prints. ;-)
Material management on a SINGLE server would be great. I do know when I was doing that across MULTIPLE octoprint instances it did get to be troublesome. Though with the way you have Repetier designed it should certainly be much easier and more reliable.
I am also going to keep an eye out on any Palette 3/3 Pro features you may add. I JUST purchased one of those the other day. Trying to scale back and up in a way. I have two small form printers (Prusa Mini and a Tronxy CRUX 1). Two really great printers. The two Geeetech A30Ts are proving to be very troublesome. Unfortunately they did not use Marlin, but instead SmartTouch (or something like that) and I have been getting VERY unreliable prints out of them. I pretty much exhausted all options on getting them to work. Everything from slicing settings, bed/gantry leveling, print temperatures, extruder tension, just about everything you can name to get a consistent print. Of course that was on TOP of all the failed hardware, boards, fans, other parts. Though I do have to say their support/warranty department has been taking good care of me in that respect. I think the mixing extruder and the proprietary firmware just doesn't fit my needs.
I'm hoping that the Palette 3 Pro and a "simpler" but larger form factor direct drive printer will be the answer. Yes a mixing extruder was nice, but very unpredictable and much too easy to clog up. With my Elegoo Neptune 2D the dual extruder setup was easier to maintain as long as I remembered to retract the filament into the bowden at the end of each print or failure. Something I was bad at admittedly. Going with a direct drive like the Prusa XL or Tronxy machines alongside the Palette should give me the results that I'm looking. At least that is the plan.
Looking forward to see what else you develop with Repetier. Best money I spent on 3D software so far. ;-)