What's helped me the most in the MU is being comfortable with wave landing on platforms and approach from different angles. Baiting grabs, maneuvering around rangs, and just trying to get reads on his intentions. I main Roy so it's a little different but the same fundamentals still apply. Powershielding is less necessary than people think in this MU imo. It's better for you if you jump the boomerang and space yourself from getting grabbed or hit by a bomb. The timing when link cant throw a boomerang is the besttime to go in. Lots of time i'm able to hop in after the initial rang toss, jump and bait the grab, or hop the returning rang and hit him with a Fair or Nair. On a stage like PS2 or Battlefield you'll likely have a platform you could retreat to if you need to hop the returning rang and dont have an opening.
Platforms are your best friend in this MU.
I don't know if there's a clear cut thing to do against link, you just need to play it all by ear and reactions to get the right reads. Overall hop or shield boomerangs, shield or avoid bombs, and take advantage of the opportunities you get to get in on link. Once you get in on him, the only thing to look out for is UpB OOS, Nair, and getting grabbed. Overall he's got a good juggle weight and is easy to combo around a bit.