One of the ways to counter shield pressure is to buffer an option using the c-stick. Doing this will allow your next move to act on frame 1 after an opponents attack, giving you the chance to escape it. Depending on what you do for the c-stick, c-stick up frame buffers a jump on frame 1 after hitstun, allowing you to attack more faster. C-stick down frame buffers a spotdodge, and c-stick either left or right frame buffers a roll. Make sure you mixup your options to leave your opponent clueless, as consistent c-stick options can be easy to read.
Because it’s the spacies, you can frame buffer during their aerials instead of their shines, although it’s possible to do so, but much more difficult to land an option.