Conditional requirements.txt

I am preparing a streamlit app for object detection that can do both training and inference.
I want to prepare a single requirements.txt file that can work whether when the app is run locally or if the app is deployed to streamlit cloud.
On streamlit cloud obviously, I won’t be doing training because of the need to have a GPU and in this case the user should clone the github repo for running locally.

Now, I come to the dependencies and requirements.txt. If I am running locally, I want to include say opencv-python but if I am running on streamlit cloud, I would want to include opencv-python-headless instead. PS: I have couple of cases like this; e.g pytorch+cuXX for local (GPU enabled) and pytorch for streamlit cloud (CPU only).

My question is how to reflect this in the requirements.txt file. I came across pip environment markers for conditional installation of pip packages, but the available environment markers cannot tell if the app is local or deployed. I wonder if there is a solution to this.