I think “running” a build/install is an acceptable choice of words.
opencv by default installs all the dlls and libs etc… into that “install” dir under its build directory. that is configurable via cmake. that location is okay to keep.
the python stuff is supposed to be sent into whatever python was found by cmake.
at least, I think so. it’s been a while since I built opencv myself. there might be a different target that copies the files to Python. if you hadn’t removed part of the log of your INSTALL build, I might be able to tell.
you’ll want to find a file named cv2.pyd or cv2.cp39-win_amd64.pyd (or cp312 or whatever python you have). you can copy that yourself into the right place inside your python installation.
here’s some mention of copying this file: OpenCV: Install OpenCV-Python in Windows
instead of the single “world” dll, you probably have a bunch of individual module dlls. you can either copy those, or extend your system PATH to include the directory where they do live. I’d suggest that be their location in the build/install/ directory (x64/vc??/bin).