2018 you should be 50A.
For the rear wall receptacle you want a
NEMA SS2-50P 125/250V] [Twist-Lock]
Not necessarily this one (white).
True Mods 50A Inlet Shore Power Supply Receptacle for RV Camper Boat [NEMA SS2-50P 125/250V] [Twist-Lock] [Low-Profile] [LED Indicator] [Dust/Waterproof] [6/3+8/1AWG Compatible] [ETL] [UV Resistant]
https://a.co/d/9Kdq22b
IF you have a 90⁰ plug, pay attention to how the inner contacts are arranged so the plug hangs down to relieve strain on the connection.
Tiny screws circled in green can be removed and the inner plug rotated. Mine only had 2 screws and the whole inside turned when I tried to get it to lock. I got it turned back where it belonged and added more tiny screws.