I have a client that regularly sends me a hundred pre cut pieces of ply to have a keyhole put in them.
Never timed them individually but a hundred takes about 30 mins.
I am flat out replacing the piece in the jig and giving them a quick sand around the keyhole before the next cycle
As others have said above, it only takes a few lines of hand written code.
Move to start position
Plunge
Move length of keyhole
Return to start position
Retract
Move out of the way while material is replaced
M1 pause and wait for restart
M47 rewind and repeat
I have a CNC router. I can not imagine why I would do these by hand, or making some jig to do likewise.