I agree with you. The DIY talks about a simple pigtail that plugs into the wall outlet and then wires to the hardwire bay. Like This. I have no issue buying this but I’d somehow need to extend it 20 feet to reach the nearest outlet.
Could I use this LAKCZIO 20 FT 12 AWG 3 Prong Replacement Power Cord, 20 Amp 12 Gauge 3 Conductor Wire Extension Cable with Pigtail Open Wiring End