If you prefer a softer bean you can extend the cooking time. Just be sure that you add additional liquid (water or stock) to make sure the beans are covered as they cook.
If you cook your mixes in the Instant Pot, choose a Natural Release over a Quick Release which will extend the cooking time.
Alternatively, you may wish to soak your beans prior to cooking which can help to reduce cook time, make them easier to digest and more tender.
QUICK SOAKING
Put the beans in a pot on the stove, cover with water by two inches, add salt if you like, and bring to a boil. Turn off the heat and let them soak for an hour. Drain, rinse and proceed with your recipe.
OVERNIGHT SOAKING
Cover your beans with water by 2 inches, add 2 tablespoons coarse kosher salt (or 1 tablespoon fine salt) per pound of beans, and let them soak for 4 hours to 12 hours. Drain them and rinse before using.