Understandable! I'm currently at 10% of his filmography seen. As a director who puts out ~2 movies a year, there's certainly a lot to choose from, and the quality wavers wildly. He's a workhorse, but always delivers some level of signature absurdity that's distinctly his.
I liked Ichi overall, but the standouts for me are his horror fare: Audition, Imprint (a banned episode of Showtime's Masters of Horror series), One Missed Call (a clear product of its time as an early 2000's J-horror), and his segment of the Three Extremes anthology.
13 Assassins is easily his most accessible of what I've now seen with little peeks of that signature Miike flavor that don't overwhelm.
Happiness of the Katakuris is a wild one if you're in the mood for musical absurdist comedy. Sukiyaki Western Django is also a trip.
Gozu is far more akin to Ichi—transgressive for transgressive's sake. Aside from those two, everything else has been more palatable in my opinion.