OP I was in your shoes. But i stuck it out focused on gaining power and slowly but surely by the time I was around level 85 I hit 50k power.

I'm now level 96 with 83k. So what I did was do everything that I possibly could focus only on 1 event ninja which took me nearly a year to get my Jonin Minato. The rest of the time I just focused heavily on refinement runes from the Group Shop, yeah they cost a lot immediately but after I 5 star my Konan started picking that up like crazy then did monthly event for even more. Its a pain in the *, all you need to do is save for rebates. Especially on Battle Armor. (I haven't worked on my Ghost Kill tactics in like 6 months).