I have tried freezer packs but there's a couple of things that makes them not worthwhile on a bike.
The heat from direct sunlight on the panniers means they're completely done within 12 hours. Everything in there gets quite warm, much hotter than if they were in a cool box in a car.
There's nowhere to re-freeze them so they are good for one cycle and you're left with the choice of carrying warm ice packs or abandoning them. Makes me feel a bit uncomfortable on the financial and environmental cost.
They also take up quite a lot of precious pannier space.
I do sometimes take frozen drinks as icepacks but either way I only get one meal on the first evening so I prefer to take something pre-made and frozen that defrosts en route.
Ambient (shelf stable) really comes into its own here. It provides good flexibility, if you arrive and there's a nice cantina open then you can leave the stuff you have on the bike and enjoy eating out. If not that's ok you have back up.
It's much closer to back packer or camping food apart from I have the advantage of being able to sous vide in a kettle.
I've just remembered there's a powdered mushroom soup that's really quite good, that might work. Maybe with some mushrooms, creamed coconut and spices I could take it in a thai direction
Perhaps bung some peppers (bell peppers) in there, they dehydrate and rehydrate well. Add a bit of colour and texture?