Ahh I didn’t notice that.
You will need to build OpenCV yourself as @crackwitz said ignore the opencv-python repo unless you want to manually build a wheel yourself. Its more straight forward to just build install OpenCV with the relavent python variables filled in
-DBUILD_opencv_python3=ON
-DPYTHON3_INCLUDE_DIR=
-DPYTHON3_LIBRARY=
-DPYTHON3_EXECUTABLE=
-DPYTHON3_NUMPY_INCLUDE_DIRS=
-DPYTHON3_PACKAGES_PATH=