My answer is quite embarrassing: out of a sudden, torch.cuda.is_available() returns True now. And, now that it does so, it’s working on the host, in both the venv and the conda env and also in another conda env using CUDA 12.1. Unfortunately for anyone ending up here via a search, I haven’t got the slightest idea what has changed in the meantime. So, sorry everyone for bothering you and thanks for the comment anyways!