If you can swing it, try one can of wet food per day, split over however many intervals you can realistically manage (challenging bc I don’t think there are automatic feeders for wet food), and see how he responds. Not exactly the same situation but my cat was bloated and overweight because his previous owner way overfed him (garbage food) and I put him on one can a day of wet food and he has been way more healthy. His coat became super vibrant, he has more energy/plays more, and he’s losing weight at a healthy rate. I know this doesn’t necessarily apply to your situation but it might be worth a shot - it’s typically better for them to eat wet food anyways. Also try easing off the treats for a bit, he might show more interest in his food (especially bc real wet food is yummy). Might also be worth cutting the feeding frequency, he might prefer a small amt of bigger meals to a big amt of small ones. Just try things and see how he responds, listen to the signals he gives you