Don't wanna be that guy but your power is looking low maybe that's why you are struggling, most people are in 16-20k region when they are reaching 70. Might be time to slow down and work on your gear/group skills/magatams/refines.
Im only at 11.5k because I dont have group skills I will be soon Im normally at 14k
group skill is very important bro. that is why most of the group leaders gets angry and remove most of the members that dont do donations. its one of the core ways to gain power. Strengthening may come after you max all your group skills.
Im earth main and I only have Kakuzu,Neji,Yamato,Orochimaru,GNW Neji, and other main ninjas like naruto,sasuke,kakashi and hinata etc. And I cant beat Sparring its so hard. I have 11K power too.