I do bananas all the time. They brown, and you have really get them dry. It’s important to let it go until there is no softness. They may look spoiled but they are not.
I do tomatoes. My wife eats them before I can get them vac-packed.
As you slice the bananas, put them into a bowl with some lemon juice for a minute or 3. Get out with a slotted spoon and put on trays. Using pineapple juice is really good too. I have not tried orange juice. Yet. :)
Debbi