they came out tasteless and gross no matter what we tried.

You tried wrong then, buy dried beans, leave them on water overnight, change the water, put them on the pressure cooker with new water for 20-30 minutes(the bean should easily be crushed between your palate and tongue if not, add more time)

open the lid, the water must barely cover the beans(remove or add water), low the fire and start adding chopped tomatoes and onions, SALT(salt is probably the most important ingredient, start with a little bit, add until the water tastes salty but edible) thyme and turmeric, same process as the salt, not too much just enough that the water tastes good, leave in a slow fire for 5-10 minutes(more if you want the beans extra soft),

bonus: extra taste secret, chop bacon and fry it with little oil, put it in with the oil, but don't put much, max two oil spoons in, do it when you put the tomatoes and onions.

Serve with rice, or add more water and make a soup.

Oatmeal: boil the oatmeal in water with cinnamon until it's cooked, then wait for cooling, put in the blender with milk, add fruits, and some drops of vanilla extract. Put in refrigerator, enjoy.

acting like people will eat them every or most days.

People do eat them everyday, rice+any grain+meat+salad+etc

You know how many tasteless and even gross things that came from animals and plants humans have learned to eat? Boil it, fry it, use every seasoning available until it tastes good.

Edit: add the salt before, when you put them on the pressure cooker, not with the tomatoes and onions, that way the taste gets inside the bean when its pressure cooked.