space. u can hit her shield with fair and uair and she cant do anything atall, same with jab, up tilt, ftilt, backwards usmash, SH dair (to poke). bair works to, but it comes out fast so you dont get as much out of ur shield stun, unless its a late bair. that might work. you can deal with her grab on reaction so all you really have to deal with is WD(move)oos - as long as you space. fsmash is a beauty, with practice you can shield poke as and when the opportunity comes.. you have to build an affinity with shield stun, size and spacing.
try AC uairing her shield -> pivot late bair -> fsmash or somethin i dunno.. the timings vary for different people. stuff like spaced jab -> pivot backflip over their shield -> dash dance uair works at the right time on the right people. learning when people go into shield is big in smash, or reacting. confuse them in the moments that they can do nothing, because you out range there oos options. try keeping them in shield through intimidation then fsmashing the exposed body. i think we have a frame advantage over grab (atleast), if we AC -> jab jab. that works on all grabs. even late fair -> jab is quicker than a grab, im not talking samus specifically here - the outspacing of an opponents oos options to gain momentum, fsmash or grab applies from all characters to all characters, its essential play imo.
late fair works to a grab if you aren't predictable with it. spacing against somebodies shield puts them in a bad position
