Are you aware that a General Practitioner (that is "your doctor") can refer you to an NHS Hospital Dietician for a detailed discussion of your diet in relation to your medical situation?
This could be at the doctors request or by you asking the doctor to arrange it.
I had one, at my request, by telephone, the dietician telephoned me, it was around 20 to 25 minutes and very valuable to me. How it worked was that the dietician had a discussion with me then afterwards prepared a report and sent it to the doctor and then the doctor forwarded it to me. So the doctor is in the loop.
It was a very pleasant process.
You might like to know, though maybe you know already, that Alpro long life no sugars soya drink one litre has no sugars and no carbohydrates. 33 grammes of protein per litre. I think of it as if it is liquid tofu with added vitamins, including B12 and D2. It has calcium added, but so does tofu, though in a different way I think. I consume one litre each day. It does contain soya so it depends on whether you are alright with soya. Some people are not. I do not know if it is an appropriate food for you but you could check it out if you choose. Unlike many products that have "no sugars" on the container this one does not have artificial sweeteners in it.
I have it spread over the day, often on Tilda microwave plain Basmati rice, though the rice does have a lot of carbohydrate in it, so I am not sure how rice relates to your dietary needs. However plain rice does not have gluten.
First stage baby food is purée and is available in a good range of flavours, often mixes. Some all vegetable, some all fruit, some a mix of fruit and vegetables. Second stage baby foods are a bit thicker. Some are high sugar, some very high, but some are very low sugar, none as far as I am aware have added sugar, it is what is from the fruits and vegetables. They do have carbohydrates, some high, some low. So which to choose depends on your particular needs. Baby food is, I understand, subject to specific high nutrition quality manufacturing regulations. I consume five sachets each day, spread over three meals, as toppings for the rice. But clearly your specialist dietary needs are different from my specialist dietary needs.
I use some of each of Ella's kitchen brand, Tesco own label brand, piccolo brand.
I don't remember if I asked before upthread, so apologies if I did and have forgotten, but have you been given a check for your vitamin B12 level? Vitamin B12 needs to be both in your food and needs to be absorbed from your food if it is there, so checking whether both are happening is worth knowing. It is done with a blood test, though a nurse to;d me that it is not done routinely at routine blood tests, but as I asked, it was included for me.