Odd wiring setup in light switch
Someone ran out of white wire

It appears the previous installers ran out of white wire to use for running neutrals, so they grabbed the spool of green wire off the back of the truck to keep the job going.  As a result, you'll need to treat the green wires in your switch boxes as neutrals for the purposes of installing your smart switch. This is workable here because you're in Chicago, land of metal conduit everywhere, and metal conduit is usable as a grounding path all by itself.

So, what I'd do is wire up the line/load pigtails to the wires that went to the switch, attach the white pigtail to the existing bundle of white/green wires (making sure they're bundled together as before), mark the green wire as a neutral with white electrical tape (given that replacing it isn't an option at this time), and either leave the green pigtail capped off/unhooked (grounding the switch via its yoke) or terminate the green pigtail from the switch on a green 10-32 ground screw in the matching hole in the back of the switch box (grounding the switch to the box via its pigtail).  If there are any other bundles of wires in the box (such as the bundle of reds in the first switch box), just leave them intact.