Another tip to reduce cutting time is to just use a faster feedrate but compensate by also increasing the RPM by the same ratio, such that the load on the tool remains the same.
I see you are running at 40ipm using 18000RPM. I’ll assume you are using a Dewalt trim router which maxes out at 27000RPM: you could use that, and feed at 40 x (27000 / 18000) = 60ipm. This should produce the exact same result. And then you can most probably push feedrate further, but that would require further experimentation.
You can also bump the speed at which the machine travels while it’s not cutting anything when moving from one letter to the next (“rapids”) by checking how much your $110/$111 parameters are. 10000mm/min seems to work fine: