Battery bank question

My system is a Winnebago TT with 400W of solar. I'm in the process of updating my battery system from 2 flooded in parallel to LifePo4. I purchased 2 100Ah batteries, but ordered the wrong size ( group 31 instead of 24. Right now I have 1 battery installed and the other as a spare.

Went boondocking earlier this week, I made some mistakes, but ran out of power after 2 days. Main culprit was not precooling the fridge. Used most of the first battery just coming up to temp.

Where I'm thinking of going with the system is to replace the active battery with a much larger one (300Ah or so) and turn the 2 100Ah batteries into a separate bank to drive an inverter. This separate bank would be charged fron the GoPower 30A controller. My thinking is this protects the main from being drawn from the inverter and minimizes there cable runs.

This doesn't prevent my stupidity, but should help.