not enough io on raspberry pi

I am rather new to CNC and want to use the new raspberry pi 4 as a control platform for my mill. I am using 4 o drives with all 8 motors each with an encoder. (3 for X, Y, Z, 1 for spindle, 1 for a lathe attachment, 2 for a 4th and 5th axis, and one more for something else I might want to add later. I also have a pump for a flood coolant system, and 6 inductive limit switch (one for each end of each axis). I also want to add a touch probe and each of the motors has a 50 mm fan. When I was adding up the pin count out of the raspberry pi i got this 2 for step direction control for each motor for a total of 16 pins. 1 for PWM or analog(I don't know which yet) for the pump, 6 for all the limit sensors, 8 for the fans and 1 more for the touch probe. All these pins add up to 32, significantly more than the 26 found on the raspberry pi. So on to my question since only the motors the touch probe and the limit switches need to be controlled in real time is it possible to communicate through serial to a slave arduino or raspberry pi to control the fans and the pump.

you can also use a mcp23x17 spi 16bit 2 port 4mhz expander
tat youcan set very fast for step dir comunication
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Thank you I think I am going to use this for all the non time critical applications

Thank you. I think I am going to use pl7i93s solution for all the non time sensetive communication. As for the latency I have no idea as I don't have my 4 yet. I would asume the 4 wouldn't have to many problems with latency as it is 3 times faster. I haven't ordered my 4 yet is there another controll platform you could recomend.

I had no idea. I will have to look into the latency on the pi

I have done a little bit of research and it appears like the latency is not a problem on the new pi4