Well, I’m not a biologist and even all my houseplants are constantly dying. For me, biology as a whole is confusing.

You are correct, but the potato plant bears potato fruits, which are classified as berries. I will clarify that in my comment.

The taxonomy in biology can be really confusing. Potatoes (only their fruits), peppers, cucumbers, eggplants, avocados, lemons, oranges, kiwifruit and papayas are also in the berry club.