Appassionata

doesn't really let up, and there's a jack section, though at the same time, someone working through the 21s can push their way through

It's easy, but the half-note runs at the end are... hmm...

I started with this. It's a 21, but not mid-tier.

The jack is harder than the half. I was very flustered at first, but I got used to it as I kept playing. It's very good for jack practice.

I got a 21 because of the jack. If you survive the jack, just twist all the half-holds to refill your gauge, then mash at the end. If you can't twist the half-holds, too bad.