Garlic and a bit of beer... Season to taste

Did you cook the carcass down with too much water?
I found several years ago that the best stock I've made came after barely submerging all the bones and stuff in cold purified water with aromatics/ celery/onion/carrots and refrigerating overnight. Then I pressure cook for several hours. Strain. Chill to pull off a bunch of the fat (there's usually a lot the way we make turkey and stuffing). I've never had to add bouillon. Then season and add the normal soup fixins celery/carrots/noodles/egg.
You may need cook it down more. Or if you're really invested, get a roaster chicken and use the stock you have to cook that carcass down too.
If all else fails, check to see if you caught covid and can't taste.

I would add a few newts, a spider or two, and one large mouse.

Sage, lots. Thyme, a bit. More Better Than Boullion& a bit of butter or oil (makes you taste the flavors more easily)

sriracha couple of dashes and some Thyme, with poultry seasoning.

Poultry seasoning. And if you like green pepper, I find it perks anything up especially anything with rice in it.

Try adding Fish sauce, xanthan gum or cornflour, whole egg whisked into the soup, splash of cream.
Join "Food Glorious Food".

You could steam some corn and green beans and add that to the soup plus some italian seasoning.

I'm by no means an expert in the kitchen, but I'm thinking you might add some rosemary, thyme, or even a touch of sage to the soup. And maybe add a bit of acid (I'm thinking citrus, maybe lemon, but I'm not sure). The other option I'm thinking of is hot spices or fresh peppers to give it a little kick.

I hope it turns out to your liking, no matter what you do.