Getting here isn't easy and getting past isn't either. Despite what the instructions say, you want to anticipate the beat and set the offset to near that point, not hear it and then react to it.

If you've already adjusted it earlier then I actually advise you to lower it. Adjusting offset too early makes bad habits but at this level you've likely haven't gotten here through those bad habits, especially considering you've said you 95-100% songs. You are also getting into territory where maybe audio sync isn't doing you justice and you should adjust the offset. You could try some other characters like The Girl In Black which makes saws easier to dodge and enemies easier to perfect. You want to PLAY the song as if you are an instrument of it, not simply reacting to the beats. You want to anticipate the beats rather than hearing and reacting to them. Do attempt the hard/fast patterns though, don't completely avoid them. Just accept the fact you finished it alive because that's a feat in an of itself and do better next time. Don't go for high percentages/grades on them and restart every time you minorly screw up (I was guilty of this once). There's also the adrenaline rush, 'the zone', from playing an extremely difficult version of a song you really like regardless of how well you actually do.

There's level 5s harder than some level 7s and same is true for some 8s and 9s. Find a couple harder songs you really like and just try them at their higher difficulty, ignore what it says the level is because it's a very subjective number. Just start trying out the level 8-9 songs and just try to get through them alive. You end up overfitting your skill to the specific songs rather than becoming generally better. It's a bit difficult due to the overall low choice of songs to practice on without the DLC (it would be nice if it was more piecemeal than $30).

Muse dash song list