Gut Surgery can cause you to develop food sensitivities. Gas is a sign you are not digesting your food well. Food that you digested well pre-surgery may no longer be. You might keep a food diary and monitor your symptoms. Look at food additives, magnesium oxide gives me horrible gas as do artificial sweeteners. Consider you might now be lactose intolerant so try and see what elimination of diary does for you.
Also consider that you most likely have depleted some of the beneficial probiotic bacteria that digest your food if antibiotics were given post surgery. I like Seeking Health Probiota12 and Klaire labs Ther-biotic Synbiotic.
https://www.seekinghealth.com/products/probiota-12-60-capsules?_pos=2&_sid=ae5f3e465&_ss=r
https://klaire.com/klairelabs/cache/file/8A17BC35-6EA2-4595-A0A845A8AA583660.pdf
Hope this helps!