More banana varieties. The reason Panama Disease was so successful is because of the practice of cloning. Every single crop is the same genetics. Researchers warned that starting over with the Cavendish would result in the exact same thing again and the clear solution was to stop cloning the exact same plant and grow more types of bananas (there are more than 1,000 species of banana and tens of thousands of varieties around the world).
Now we're dealing with TR4 because of the Cavendish being grown in the exact same way but with an even heavier reliance on pesticides, slavery, and violent control over local power.
That was a fun bit of trivia I learned from Balatro - the Gros Michel has a one in six chance of being destroyed after a round. However, if it is destroyed (the game displays Extinct! when it perishes), then the Cavendish can appear randomly in the shop and has a one in one-thousand chance of being destroyed.
And they aren't even cloning anything even close to the tastiest bananas, just the ones best suited for transport/storage.