Communication between two STMs over 2 meter with small latency
The only problem with SPI you have to face is clocking speed and distance - if the clocking speed is too high then the data coming back from the slave might be too much misaligned to be able to adequately receive it. That's the short story.

So, if you transmit at 128 kbps then the clock is 128 kHz and one symbol of data is approximately 7.8 us. You then have to consider how long it takes for a data to fly down the cable and that is based approximately on 70% of the speed of light.

Light travels 1 metre in 3.33 ns and so 2 metres of cable takes about 10 ns to be received and, when the slave responds, it does so on clock edges that are 10 ns "late" compared to the master's perception of time so, there's another 10 ns to add on to the overal skew of data coming back to the master.

So, 20 ns of skew in a basic clock period of 7.8 us isn't really going to be a problem.