Looking for an understable midrange or fairway for a minimal bag.

I am limiting myself to an 8 disc bag as I am still very much learning. My form recently had a big improvement, getting the nose down and losing a lot of OAT. But now I find my self repeatedly failing to get turn out of my Hex and River... Before this I wanted to get rid of the River as it was too understable...

So I am looking for something more understable than those to use between 200-300ft.

For reference I 280-300ft with my fairways and 330 with my Trail.

EDIT: Also welcome are form-cue tips! If you think "this sounds like he is doing this and that wrong" let me know:)

EDIT2: Thank you all for your comments, I'm probably getting a Stig. It looks perfect!

Edit3: Stig arrived this morning, and I went for a round with it right away. Its perfect. Amazing flights and the mold feels like its made for my hand.