My apologies I didn't mention i am coeliac and very recently dairy free which is absolutely killing me, I used to eat 1/2 lb a week......
All GF foods are loaded with extra fats and sugar to make them palatable....
My guts HATE ME !!!!!!
I am gluten-free, although I am fine with dairy - so far.
I am fortunate to have a very supportive partner who is the main cook in our household. I do breakfast and maybe a very light lunch, but he does all the main meals.
When diagnosed T2, I adopted a reduced carb diet - reduced, not zero, and at that time I found I just gave up bread anyway. When I was forced to go GF, I thought it'd be a cinch, because I wasn't eating many grains at all, but of course, gluten lurks in unexpected places.
One of the simplest ways we have found to avoid gluten is to minimise processed foods. Fortunately, ready meals were never big in our meal plans anyway.
So, to your challenges.
Have you tried batch cooking at the weekends, or asking your wife to do some for you? The beauty of many things that are batch cooked is they can go into the freezer for "another day", and over a brief period, you can build up a bit of a bank of food.
In your shoes, I'd look at building my meals around protein, so things like chicken drummers/thighs, high meat content sausages, eggs, and so on. I find protein fills me up and with fattier cuts of meat, like chicken thigh (as opposed to breast) there is some fat in there, which can help take in come calories to keep you going. Cooked bacon can be delicious and good cold as well as hot. Pork ribs, stews/casseroles in flasks can work well too.
Things like the chicken pieces can be cooked, cooled, then individually wrapped in foil before popping into the freezer. Once defrosted, they can even become finger food, because you can fold them by the foil covering. On the move I'm a big fan of chicken, as you can probably tell!
Do you have a fridge or freezer in your truck, if you are on the road all week? That might take a bit of figuring out and trial and error.
My steer would be to try a few things, but not to expect a perfect solution day one. These things tend to develop over time.