Mac build doesn't work for SM6, but works for SM5

Hi, I am trying to get a ue5 build working for SM6. Everything is normal on a SM5, M1 mac, but on an M4 running with SM6 plays it, it has numerous issues:

  1. Networking seems to have lots of weirdness, not allowing connecting, and not allowing creating servers/map travel (most of the time)
  2. Most importantly, nothing is rendered, everything is grey, except the UI. (turning the player does change the colour of this grey, weirdly). But the UI is fine. Footsteps also work, and it sounds likely that the player is probably moving.

Also, I am getting heaps of no metalmap found errors:

LogMetal: Display: No .metalmap file found for global_sc_sf_metal_sm6-metal_sm6!
LogMetal: Display: No .metalmap file found for paper2d_sf_metal_sm6-metal_sm6!
LogMetal: Display: No .metalmap file found for aclplugin_sf_metal_sm6-metal_sm6!
LogMetal: Display: No .metalmap file found for animatorkit_sf_metal_sm6-metal_sm6!
LogMetal: Display: No .metalmap file found for physicscontrol_sf_metal_sm6-metal_sm6! LogMetal: Display: No .metalmap file found for deformergraph_sf_metal_sm6-metal_sm6!
… etc

Any help would be appreciated, thanks!

Also, I am running 5.8 with xcode 26.3 and building from macos 15.7.7