30 amp is the 120v rating 55 amp is the 12v rating.
With 2 batteries 35 amp is fine or spend more to get 55 if you like. Rare to draw more than 10 amps DC to run a trailer.
Three stage charging is very important when off-grid.
PD 4000 series, 3 stageThis one is 30 amp AC in and distribution with a 45 amp DC 3 stage converter.
Will work perfectly for what you need.
Forget anything that says WFCO. These are advertised as 3 stage but never seem to actually shift into boost mode and float mode is pretty hit or miss. In all practicality it is a slow charging 13.6 fixed voltage supply.
