Happy Holidays!
GR2 has crankset with 2 types of spindle either DUB or Shimano Hollowtech. So whichever standard you choose will decide your bottom bracket..
I have used the Gr2 with an AXS XX1 rear derailleur and an e-thirteen 9-50 cassette with no issues. I used a different bottom bracket than the one it shipped with because I had a higher quality one on hand.
If you haven't bought your crankset yet I could sell you mine. I picked up a force carbon crankset with power meter for cheap so I planned to switch it out. My Senicx is 175mm arms and 42t chainring.
I use it. GX axs with senicx gr2. No problem whatsoever.I changed recently the chainring to a pass quest just because of the looks, but the senicx was fine with a SRAM chain