The way I have been served congee was as a very plain base. It was white rice based but done pretty much with straight water so it was the rice version of oatmeal.
The reason is so everyone can customize as they want, like an oatmeal bar, but savoury.
When I make it for myself, I know what I want so those things are built in. First thing is the broth. I do it with tons of garlic, ginger, dried mushrooms, a few spices and some lemongrass. Chicken pieces are poached in it until cooked then the meat is stripped off and the bones, skin and bits are put back in.
After a few hours on the stove, it's strained and all but the mushrooms is thrown out. ( I put the mushrooms in dry and they tend be good for chopping by the time it's done)
Then the rice is cooked in the broth until it's broken down but not completely smooth. I do it a bit thicker than most restaurants. The poached chicken, the mushrooms, some fresh greens and maybe some dried fried onions are about all that are added to it aside from a drizzle of soy sauce and rice wine vinegar.
Very warm, comfortable and soothing and it freezes well.