this match up is pretty bad for link. she's too fast, you're too slow, your projectiles don't work, all of your aerials are punishable and you can't edge guard her easily.
with that said here's how i play it
try to keep her at the range where boomerang is safe. this range is around the length of your zair. this range makes a lot of your moves safe and makes her moves punishable on reaction if she whiffs. footsies is key. keep moving, it's ok to run backwards and give up some stage control if it makes her whiff a move. pivot grab, ftilt and fsmash are really good. don't let her run up on you easily, block her out with boomerang, bombs, zair, nair and fsmash. if she gets too close, grab, usmash or nair OoS.
you shouldn't approach her ever, her projectiles aren't good enough to force you to go to her. stay back and punish anything stupid that she does.
bomb canceling will be one of your best tools to get out of her tilt locks and resets. if you don't know how to do it, basically anytime you're holding a bomb you can press down-b to combo break her. the problem lies in her ability to punish bomb pulls. so know how to zair with bomb, and when it's safe to pull bombs. other than that, try to SDI away when she tries to combo you, but DO NOT waste your second jump.
as soon as you use your second jump poorly, you're ****ed. i'm pretty sure all of her aerials beat your nair, which means you can't do anything to get down. dair isn't reliable enough if she's hitting you from the correct angles, so don't try to rely on that. recovering is going to be hard because she can hit you from any angle off stage.
when recovering try to use your second jump as late as possible. this gives you more mix ups with your recover pattern. whenever you get hit hard, DI to the top corners of the stage and cancel your tumble with a bomb pull and NOT your second jump. cover your return to the stage with projectiles but take notice of when she tries to attack you off stage. if she's jumping out too early, recover above her and throw a bomb on top of her head. if she's trying to wait until you're closer to the ledge, recover low and get ready to wall tech just in case.
to win this MU you have to out play her, it's as simple as that. you need to have perfect spacing, punishment, DI, recovery and reads (rolls/spot dodges/tech rolls, air dodges, whiffs etc)