Having re-read your requirements here is my suggestion.
Forget having 12VDC distribution and do it all at 120VAC
2x sok batteries for 5273.6 watt hours
One of these for dc2dc charge capability
The KISAE DMT1230 DC to DC Battery Charger is a multi-stage, multi-input battery charger capable of charging different types of batteries commonly installed in boats, RV's, 4WD's and commercial vehicles.
www.donrowe.com
Gives you the option for solar panels if you ever want to go that route.
One of these
https://www.donrowe.com/samlex-evo-1212f-hw-pure-sine-inverter-charger-p/evo-1212f-hw.htm
Gives you an ac charger, low frequency inverter, automatic transfer switch and configurable low voltage disconnect so you don't ruin your batteries.
Plus a ton more features that are only practical with an integrated solution.
Then all you need is fuses and wires.
Have you considered going 24 volts?
They make a 24 volt version of that inverter/charger and there good 12->24 volt dc2dc chargers from sterling and Victron.