Look, you completely missed what i was saying before.
I worked a bit with ultrasound like signals, and all that signal processing stuff is quite similar to what is used in cases like Xterra and Equinox. Same dds-demod-multirate filter etc. So in our case one channel (I or Q) with DDS, demodulator and post demod mutltirate filter was consuming around 50 operations per sample with 32 bit integers. Actually some accumulators were wider than 32 bits, but not that important. Assuming that equinox processing is similar, works with four frequencies, has sampling frequency of 100kHz for simplicity, we are getting 80 millions of these calculations per second. It is already a significant portion of what M7 core can do at 200MHz.
You keeps assuming that all it does is scans buttons and lights up segments on display, which is completely wrong.