Like you I’m in week 4 – 2 more days to go. And like you, weight loss has been a tad slow after the initial week. However, I started keeping an eye on carbs at the beginning of this week and so far, have dropped 2lb, which is an improvement on weeks 2 and 3. The general consensus seems to be to try and keep carbs below 50g per day. I have actually been hitting considerably lower than that, but as much because the foods I have been choosing have accidentally been low carb, rather than actively seeking out those with particularly low-carb content. I haven’t worried too much about the ratio carbs to fats to protein. Have just been ensuring I have full fat everything to help me feel full for longer and kick into fat burn mode and to eat plenty of high protein foods.
There does seem to be an anomaly reported on various threads, which seems to suggest that for many, between weeks 2 and 4 are a bit of a plateau, when weight loss is low to zero and that if you just keep to your 800cals a day, the weight will eventually start to drop again.
It certainly sounds like you are sticking to the 800 cals, so you could just continue as you are and the weight should begin to drop again soon. On the other hand, it can’t hurt just to check that there is nothing you are eating, that has a surprisingly high carb count.
Not sure any of this helps much, but this is how I have tackled a similar situation.