I don’t know, if OpenCV might have uninstalled PyTorch for some reason, but it would be shown during the installation.
I would try to create a new environment, rebuild PyTorch, and make sure it’s working.
Afterwards, you could check, if the conda OpenCV installation would remove PyTorch again and if so build OpenCV from source.
I guess you are also using an older PyTorch branch, since the current one would support a minimal compute capability of 3.5.