Electromagnetic interference to my project
This is a situation that demands a clear understanding of pulse spectrum from V=LdI/dt  and Ic=CdV/dt where 1st fourier spectrum is continuous  up to f=0.35 Trise time with a null then repeat with diminished harmonics to 2f, 3f and so on.
So it is effectively a broadband noise generator.
And you have a smorgasborg of noise and antenna and inductive/capacitive coupling factors on cables. * Like an all you can eat diner for EMI.*
The general EMC categories of solutions are :

Isolate the noise radiators from the sensitive inputs by reducing paired loop area. and separation and right angles of cable routing.
Balance the paired wires of both radiators and receivers by twisted and/or shielded pairs
reduce common mode leakage out and in by improved Balance for frequencies above 1Mhz or spikes &lt;&lt; 1us rise time by careful selection of CM chokes, balun or toroidal choke over pairs, (just like ethernet PHY)
apply LPF , low pass filtering methods to data lines with RF caps, feedthru caps such that data rate is not loaded but with impedance ratio of series CM choke and shunt RF cap you achieve greater differential attenuation. Thus can also include surge limiting switched capacitive loads, soft start to motors, commutation snubber filters
improved grounding so that ground shifts from switched loads do not affect data ground or analog grounds, with low L.  braided wire or Litz wire in high current apps flat straps or heavier gauge wire (albeit still inductive.)
add transient snubber directly across inductive load such as RC for AC loads and reverse diode shunt for DC inductive coils relays etc.
include ESD protection in your solutions