cuda-cccl will clobber cuda-thrust:
$ mamba create -y -n thrust cuda-thrust -c nvidia
$ mamba activate thrust
(thrust) bash-4.2$ grep "^#define THRUST_VERSION" $CONDA_PREFIX/include/thrust/version.h
#define THRUST_VERSION 101201
(thrust) bash-4.2$ mamba install cuda-cccl -y -c nvidia
(thrust) bash-4.2$ grep "^#define THRUST_VERSION" $CONDA_PREFIX/include/thrust/version.h
#define THRUST_VERSION 200001
(thrust) bash-4.2$ mamba list
# packages in environment at /home/burt/.conda/envs/thrust:
#
# Name Version Build Channel
cuda-cccl 12.1.109 0 nvidia
cuda-thrust 11.4.43 h00096a5_0 nvidia
The conda-forge folks handled the similar issue with cub by adding constraints on cuda-cccl in the cub package.