Exams after a point do mostly need specific ninjas. If the difficulty level is not being reduced, it needs even a combination of stronger ninjas and power. Sage Naruto is the key until a point of exams and later on you need something more exclusive to pass them. There is not always a solution to all the exams with any ninja. There is always a key ninja to be able to beat them.

For example in the above exam, you'll need to stop Hiruzen for example if he dies, because his seal will 100% kill your main damager (Which will probably have full hp there). Naruto and Gaara can do mostly the job till the 340 stage at least, did not try them further myself. I'd suggest you to collect Sage Naruto fragments from the collection system slowly, he'll help you for few stages at least if you skill trial him a bit .Otherwise, Kakuzu is excellent for exams, changing his support ninjas will help you beat almost every single exam stage. Are you close in getting him 4*? He is being offered almost every cycle now, so it should be easy to collect some fragments weekly and once a synergy with Fukurokumaru's Deals shows up to finish him.