Li batteries are not necessary for 12v fridges, they run just fine on any battery.
I just did a weekend trip to the mountains. Parked in the forest under heavy canopy of trees with the fridge running. It did fine the first night of course with full charge, then the next day in late afternoon the fridge still said 13.6 volts, which is full charge. This is from 200 watts of solar under partial shade (some light always gets through the trees).
I would have done at least 300 watts of solar if to do again, but my 200 is in series and I havent figured how to add one more panel. No room for two. Maybe I can add the third panel is series too....