I am currently studying for my Platform Developer 2 Exam and the material to cover is seemingly endless but you slowly get through it. If you go to the Platform Developer 2 Certification page, you will find a path of prerequisites that need to be met prior to taking it. These four superbadges make up about 50% of the material that Salesforce suggests you cover before the exam. The rest of the material can be found in this Developer 2 trail mix, adding up to a whopping 94 hours and 15 minutes of content! I finally got through all of the super badges and have about 33% of the trail mix left before I can actually start studying for the exam. If anyone is looking for a great course with good material to cover, I have used Focus on Force for most of my exam prep.
Road to Platform Developer 2 Exam