The push in back wire is so cheesy that its almost criminal. Thankfully the code allows wire no larger than 14 gauge and the hole is small enough you cannot get 12 gauge thru it. I refuse to wrap around a screw on an outlet. I buy the commercial/industrial backwire design that you insert the wire and tighten the screw and a knurled or serrated plate is drawn up to clamp the wire inside. If you tighten them properly they won't work loose.
Frankly, every couple of years you should go thru an RV electrical system and re-tighten everything, going so far as to open up transfer switches and other boxes that contain connections to tighten.
If you are interested in not having screws to work loose, use the Hubbell SnapConnect® type receptacles and then use the WAGO connectors to make the connections to the Romex™
https://www.hubbell.com/wiringdevice-kellems/en/Products/Electrical-Electronic/Wiring-Devices/Straig...https://www.wago.com/us/lp-221RV receptacles are designed and certified to be installed without a separate box. They ARE the box. I wished someone made a better version of them however, with quality connections and heavier spring tension contacts for the plugs to engage with. At home I use all commercial stuff that is actually difficult to plug into, but you get good contact.
Charles
'03 Ram 2500 CTD, 5.9HO six speed, PacBrake Exh Brake, std cab, long bed, Leer top and 2008 Bigfoot 25B21RB.. previously (both gone) 2008 Thor/Dutchman Freedom Spirit 180 & 2007 Winnebago View 23H Motorhome.