> Python version is super laggy, something to do with OpenCV
Most probably I'm wrong, but I wonder if it has anything to do with all the text being written to stdout. In the odd chance that it happens on the same thread, it might be blocking.
I’m not sure what your reasoning is, but note that blocking I/O including print() releases the GIL. (So your seemingly innocent debugging print can be extremely not harmless under the wrong circumstances.)
Hmm, I couldn't remember if I tried it without the text being written to stdout. But that's an interesting point, I just didn't expect the print() blocking to be significant.
Most probably I'm wrong, but I wonder if it has anything to do with all the text being written to stdout. In the odd chance that it happens on the same thread, it might be blocking.