I would never cook zucchini or any soft vegetable that you want to remain whole in a pressure cooker. That would include all the summer squashes. Winter squashs cook fast and well in a pressure cooker as well as potatoes and carrots. When I was cooking a lot, I used the instruction book that came with my Mirror pressure cooker. In addition to instructions on how to use the pressure cooker it had a chart listing how long to cook various foods and many good recipes combining ingredients. It helped me know what was good cooked in a pressure cooker and how to convert recipes for the pressure cooker. My book said to not cook rice in a pressure cooker. I don't remember why.
This was before many cookbooks were available. I suggest finding a pressure cooker book to use. I find many of my cookbooks at low prices at Barnes and Noble. Amazon on line also has good prices. You probably can find this info on pressure cookers on line too. You can check at the library .too.
I suggest that pork tenderloin is best baked in the oven. It is so tender it's best cooked with dry heat cooking meat with water should be reserved for other cuts such as chops and some roasts.
I suggest you get a basic cookbook to learn about different ways to cook. I learned with Betty Crocker. Joy of Cooking is a good one, too. You can find cookbooks in a thrift store.