I think your doing just fine.
I hit the wall of 99% acc consistency at 5.5 stars. How does 6 star work.Man you needa push yourself. Nearly all my friends who started playing 3 years ago with maybe 7-10b ranked score are like under rank 500 now.
What I've been doing is grouping by difficulty rating and sorting by bpm. Then I do a search of bpm>=180 stars>5. Playing in order by bpm with relatively the same star range has been pretty nice training. You can change the search methods to find what suites you.