late aerial waveshine back is safe for the spacie if done right. your best bet is to mixup what you do before you shield by either dash farward or backwards into shield same goes for wd into shield back or forward. to extend on that you can tilt your shield upwards.
if you do all of these things sometimes, the spacie have a harder time spacing correctly and thus they cant fully rely on muscle memory.
if you force them to react or second guess themselves they are more likely to mess up an lcancel and you can shield grab before the shine hits your shield.
apart from that buffering a roll, buffering a jump (with cstick, while holding shield) and wavedashing back out of shield are good options.
again, dont be predictable with what you wanna do, or else the spacie player will pick up on that and simply touch your shield with anything and punish the roll.
hope that helps