Using the GPU typically involves extra latency, especially when done via friendly APIs in Python. For large NN that is typically dwarfed by number of FLOPS so no big deal. For real-time control, with minimal flops and a low latency / high frequency demand it is likely not the best fit.
I’d also question why Python? If you implemented that loop in C or C++ and replotted your graph, it’d be hard to compare any of the existing measures on the same scale. There is so much extra overhead under the covers of any Python app, you’d likely get a 100x+ increase on the CPU writing it in C++ for an algo like that.