I think they mean .8Ah for the circuitry/board of the Dometic frig and it runs on propane.
I don’t think you can have too many amp hours. You might also want to think about going Li-Ion so you can run the battery down to a lower percentage.
We’ve found that we can easily make an entire weekend with our 2 normal batteries in one spot if we run the generator about an hour each day. If we are moving around like at Yellowstone, we almost never have to run the generator. Changing to all LED lights made a huge difference. Also, keep in mind that newer tvs use a lot less power.