You can add ALL SORTS of stuff to cottage cheese and plain yogurt (greek works better for savory IMO) It's pretty easy really, just find a seasoning or mix or marinade mix that you enjoy, and mix a bit into the cottage cheese or yogurt. It's going to take some experimentation to get a flavor that you are happy with, but it's legit just as easy as mixing in some premixed powders. And you can add some unflavored protein as well to boost your protein intake.
My pre-op was SF jello, watermelon, protein shakes and celery (I could eat as much of this as I wanted)... celery was my go to, since I could eat as much as I needed but it got old very quickly. So I started coating up pre-cut celery with seasonings like "Pub Burger" seasoning or "Maple Bacon" seasoning. And boy did that make things easier to deal with! So, go crazy, find yourself some seasonings you are interested in and start mixing them into your approved foods and just go wild! You never have to sacrifice flavor during this whole process, you just need to play around a bit.