Taki Study discussion:
against 1B,A-->PO A (fastest input) Voldo's SSR A+B wins everytime. The sidestep avoids the first hit of PO A consistently and A+B tech crouches the second hit. You can actually passively SSR when you have similar frame (dis)advantage and confirm what to do. Also, I had trouble stepping it consistently at first as well. Taki has alot of frame advantage so you have to step pretty late after the block. After realizing that, its definitely possible to work into gameplay.
Edit:
So it does seem character/step class specific. Voldo, Cervy, Asta, Amy, etc. can SSR PO A at -2 while the sisters, taki, raph, lizzy, etc cannot