Some greens actually make things worse. Brussels sprouts, broccoli, cabbage, asparagus, and cauliflower www.healthline.com/health/foods-that-cause-gas
As a lifetime veggie, you get used to thinking about this and it does get worse as you get older. You have to experiment and sadly you perhaps have to avoid certain foods. Onions and garlic especially become indigestible to an older gut. You might find wheat and milk products are a problem, lactose intolerance gets commoner as you get older, lactose free milk is now easily available.
People say try fermented products like kefir and sauerkraut, I don't like them. I have found that a good probiotic makes a difference, try Holland and Barrett.
I've also become addicted to camomile and honey tea!
Hope that helps.