Not that I expect this to have fantastic performance, but I think your benchmark is cheating. Locally hosted Jupyter is going to have significant overhead compared to a straight Python interpreter.
python command line 247µs
local jupyter lab 274µs
jupyter lite 4ms (about 16 times slower than the other two)
Honestly considering how jupyter lite is working, I still feel this is pretty good.I do not care about the performance of jupyer lite - that it runs at all is a miracle. That it is acceptable performance for doing demos/teaching from a browser is simply magic.