First and foremost, follow any dietary advice and take any supplements that were given to you by your Dr. post operation. You’ll only be able to have liquids for the first couple of days following surgery and then work up from there.
It is important that you make Blasts that will give you enough protein, healthy fats, vitamins, and minerals - more nutrient-dense since you will be eating less food overall.
Since the digestive tract hasn't been altered you should be able to eat the same foods without any nutrient malabsorption.
Small, frequent meals or Blasts. Introduce foods back slowly to figure out which foods your system can and can’t tolerate. The NutriBullet should pulverize everything to liquid form, however you may wish to skip out on super-fibrous foods at first like celery or pineapple.
It will take some experimenting, however I'd recommend to start with ones that won't cause gas or bloating. https://www.nutriliving.com/blog/feeling-bloated
Good nutrient-dense foods to add to a Blast include legumes, avocado, nuts and seeds (if these don't bother you), nut butters, coconut oil, protein powder and certain oils like flax or cold-pressed coconut.