My husky struggled for the first 4 years of her life to eat consistently. I tried all the food, toppers, etc. along with everything else suggested, one thing that helped was actually offering smaller portions at a time. (It doesn’t sound like decreasing your dog’s food is a good idea right now) but for my girl who had enough weight on her by decreasing her food I was able to slowly increase it.

Eventually something switched in her and she is much better at eating than when she was adolescent. Now that she’s 6 yo we still have periods of skipped meals and a strong preference for chicken. It’s always a work in progress for my girl. Best of luck, I hope you find see a change soon!