There are a couple of collisions between the mesa-vulkan-drivers.i686 and the mesa-vulkan-drivers.x86_64 packages. The following files are included in both packages:
/usr/share/drirc.d/00-radv-defaults.conf
/usr/share/vulkan/implicit_layer.d/VkLayer_MESA_device_select.json
Koji doesn't list libjack as one of the provides of the Carla package anymore, so #1663357 should be fixed. Installing the package pulls in jack-audio-connection-kit and liblo and carla launches without any errors about missing libraries/modules.
Installing packages that depend on libjack.so.0 with updates-testing enabled now no longer causes Carla to be installed instead of jack-audio-connection-kit, so the issue should be fixed. Koji still lists libjack.so.0 as one of the "Provides" of the Carla package though, but I'm not sure if that is an issue.
Tested it using a custom build of pymol on Rocky 8 and it is working fine here.