I'm not too worried about the chainstay length, I've had a frame with this one before and really didn't feel any difference with a 435mm chainstay frame for example. It will leave more room for the tires so it's not bad.
For the transmission I have a SRAM GX AXS groupset, Sid SL Select fork, carbon handlebar-stem combo, Elita or Reverb AXS seatpost depending on the terrain, Light-Ride carbon wheels with Goldix hubs (1205g), SRAM level ultimate brakes .