The only studies I saw did not cross-pollinate. There's stuff on how low carb seems to help a person age more gracefully, with better health. And then the studies which seem pertinent to your situation focus on how our twinned senses of taste and smell seem to diminish as we age.
The fact that you can still enjoy bacon and sausage is a clue that made me think you could try Smell Training.
It's likely that your brain is confused by the feedback it is getting, and that's why the signals have changed. Instead of cream sauces, which are a subtle buffer for flavors like garlic and dill, try different and more assertive spices.
I love Penzey's blends:
Cajun seasonings can help you make "blackened" steak and pork, which is about the spices, not the level of doneness.
Are you okay with dairy? I've found whole milk yogurt mixed with whey protein creates an easy, filling, meal with things like cocoa, raspberries, or flavor drops with sweeteners that you get along with. A little dab will do ya.
If satiety is the problem, it might be that you aren't getting enough
protein. Our digestion efficiency can also diminish as we age. I love Italian cold cuts -- when I had a serious appetite issue, that was still appealing.
My own experience was transforming when I cut back temporarily to ONE food (hamburger with salt and pepper) and was amazed as how good it tasted
For me, there were whole categories of food which were literally doing me more harm than good. I couldn't get better until I got them out of my way, and off my plate.
Food allergies can create all kinds of symptoms. Mine went undetected for a long time because none of them were digestive symptoms! It's possible that is part of the problem, so I wanted to mention it.
The smell training site I linked focuses on your problem, so good luck!